Only set ssh connection params if transport is ssh (#1224)

Skip setting various additional connection params if the transport for
the libvirt connection is not ssh based as these will be ignored and may
cause confusion as to why they do not apply.

lib/vagrant-libvirt/config.rb

@@ -711,11 +711,25 @@ module VagrantPlugins
           uri = 'qemu' # use QEMU uri for KVM domain type
         end
 
+        params = {}
+
         if @connect_via_ssh
           uri << '+ssh://'
           uri << @username + '@' if @username
 
           uri << ( @host ? @host : 'localhost' )
+
+          params['no_verify'] = '1'
+
+          if @id_ssh_key_file
+            # set default if using ssh while allowing a user using nil to disable this
+            @id_ssh_key_file = 'id_rsa' if @id_ssh_key_file == UNSET_VALUE
+
+            # set ssh key for access to Libvirt host
+            # if no slash, prepend $HOME/.ssh/
+            @id_ssh_key_file.prepend("#{ENV['HOME']}/.ssh/") if @id_ssh_key_file !~ /\A\//
+            params['keyfile'] = @id_ssh_key_file
+          end
         else
           uri << '://'
           uri << @host if @host
@@ -723,18 +737,10 @@ module VagrantPlugins
 
         uri << virt_path
 
-        params = {'no_verify' => '1'}
-
-        if @id_ssh_key_file
-          # set ssh key for access to Libvirt host
-          # if no slash, prepend $HOME/.ssh/
-          @id_ssh_key_file.prepend("#{ENV['HOME']}/.ssh/") if @id_ssh_key_file !~ /\A\//
-          params['keyfile'] = @id_ssh_key_file
-        end
         # set path to Libvirt socket
         params['socket'] = @socket if @socket
 
-        uri << "?" + params.map{|pair| pair.join('=')}.join('&')
+        uri << "?" + params.map{|pair| pair.join('=')}.join('&') if !params.empty?
         uri
       end
 
@@ -755,7 +761,6 @@ module VagrantPlugins
         @connect_via_ssh = false if @connect_via_ssh == UNSET_VALUE
         @username = nil if @username == UNSET_VALUE
         @password = nil if @password == UNSET_VALUE
-        @id_ssh_key_file = 'id_rsa' if @id_ssh_key_file == UNSET_VALUE
         @socket = nil if @socket == UNSET_VALUE
 
         # If uri isn't set then let's build one from various sources.