DEV: stop freezing frozen strings

We have the `# frozen_string_literal: true` comment on all our
files. This means all string literals are frozen. There is no need
to call #freeze on any literals.

For files with `# frozen_string_literal: true`

```
puts %w{a b}[0].frozen?
=> true

puts "hi".frozen?
=> true

puts "a #{1} b".frozen?
=> true

puts ("a " + "b").frozen?
=> false

puts (-("a " + "b")).frozen?
=> true
```

For more details see: https://samsaffron.com/archive/2018/02/16/reducing-string-duplication-in-ruby

script/bulk_import/base.rb

@@ -26,7 +26,7 @@ module BulkImport; end
 
 class BulkImport::Base
 
-  NOW ||= "now()".freeze
+  NOW ||= "now()"
   PRIVATE_OFFSET ||= 2**30
 
   # rubocop:disable Layout/HashAlignment
@@ -660,7 +660,7 @@ class BulkImport::Base
           imported_ids << mapped[:imported_id] unless mapped[:imported_id].nil?
           imported_ids |= mapped[:imported_ids] unless mapped[:imported_ids].nil?
           @raw_connection.put_copy_data columns.map { |c| processed[c] }
-          print "\r%7d - %6d/sec".freeze % [imported_ids.size, imported_ids.size.to_f / (Time.now - start)] if imported_ids.size % 5000 == 0
+          print "\r%7d - %6d/sec" % [imported_ids.size, imported_ids.size.to_f / (Time.now - start)] if imported_ids.size % 5000 == 0
         rescue => e
           puts "\n"
           puts "ERROR: #{e.inspect}"
@@ -669,7 +669,7 @@ class BulkImport::Base
     end
 
     if imported_ids.size > 0
-      print "\r%7d - %6d/sec".freeze % [imported_ids.size, imported_ids.size.to_f / (Time.now - start)]
+      print "\r%7d - %6d/sec" % [imported_ids.size, imported_ids.size.to_f / (Time.now - start)]
       puts
     end
 

script/bulk_import/discourse_merger.rb

@@ -4,7 +4,7 @@ require_relative "base"
 
 class BulkImport::DiscourseMerger < BulkImport::Base
 
-  NOW ||= "now()".freeze
+  NOW ||= "now()"
   CUSTOM_FIELDS = ['category', 'group', 'post', 'topic', 'user']
 
   # DB_NAME: name of database being merged into the current local db

script/bulk_import/vanilla.rb

@@ -209,7 +209,7 @@ class BulkImport::Vanilla < BulkImport::Base
 
       User.find_each do |u|
         count += 1
-        print "\r%7d - %6d/sec".freeze % [count, count.to_f / (Time.now - start)]
+        print "\r%7d - %6d/sec" % [count, count.to_f / (Time.now - start)]
 
         next unless u.custom_fields["import_id"]
 
@@ -276,7 +276,7 @@ class BulkImport::Vanilla < BulkImport::Base
 
       Post.where("raw LIKE '%/us.v-cdn.net/%' OR raw LIKE '%[attachment%'").find_each do |post|
         count += 1
-        print "\r%7d - %6d/sec".freeze % [count, count.to_f / (Time.now - start)]
+        print "\r%7d - %6d/sec" % [count, count.to_f / (Time.now - start)]
         new_raw = post.raw.dup
 
         new_raw.gsub!(attachment_regex) do |s|
@@ -613,7 +613,7 @@ class BulkImport::Vanilla < BulkImport::Base
           )
         end
 
-        print "\r%7d - %6d/sec".freeze % [count, count.to_f / (Time.now - start)] if count % 5000 == 0
+        print "\r%7d - %6d/sec" % [count, count.to_f / (Time.now - start)] if count % 5000 == 0
       end
     end
 
@@ -645,7 +645,7 @@ class BulkImport::Vanilla < BulkImport::Base
           end
         end
 
-        print "\r%7d - %6d/sec".freeze % [count, count.to_f / (Time.now - start)] if count % 5000 == 0
+        print "\r%7d - %6d/sec" % [count, count.to_f / (Time.now - start)] if count % 5000 == 0
       end
     end
   end

script/bulk_import/vbulletin.rb

@@ -608,7 +608,7 @@ class BulkImport::VBulletin < BulkImport::Base
       count = 0
 
       Dir.foreach(AVATAR_DIR) do |item|
-        print "\r%7d - %6d/sec".freeze % [count, count.to_f / (Time.now - start)]
+        print "\r%7d - %6d/sec" % [count, count.to_f / (Time.now - start)]
 
         next if item == ('.') || item == ('..') || item == ('.DS_Store')
         next unless item =~ /avatar(\d+)_(\d).gif/

script/import_scripts/mbox/support/indexer.rb

@@ -39,7 +39,7 @@ module ImportScripts::Mbox
 
     private
 
-    METADATA_FILENAME = 'metadata.yml'.freeze
+    METADATA_FILENAME = 'metadata.yml'
     IGNORED_FILE_EXTENSIONS = ['.dbindex', '.dbnames', '.digest', '.subjects', '.yml']
 
     def index_category(directory)