Handle whitespace, add separator to regex in set_directive_lines

We added the separator to the regex in set_directive_lines to avoid
grabbing just a prefix. This doesn't allow for whitespace around
the separator.

For the Apache case we expected that the separator would be just
spaces but it can also use tabs (like Ubuntu 18). Add a special
case so that passing in a space separator is treated as whitespace
(tab or space).

https://pagure.io/freeipa/issue/7490

Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>

ipaserver/install/installutils.py

@@ -565,11 +565,15 @@ def set_directive_lines(quotes, separator, k, v, lines, comment):
         v_quoted = quote_directive_value(v, '"') if quotes else v
         new_line = ''.join([k, separator, v_quoted, '\n'])
 
+    # Special case: consider space as "white space" so tabs are allowed
+    if separator == ' ':
+        separator = '[ \t]+'
+
     found = False
     addnext = False  # add on next line, found a comment
-    matcher = re.compile(r'\s*{}'.format(re.escape(k + separator)))
-    cmatcher = re.compile(r'\s*{}\s*{}'.format(comment,
-                                               re.escape(k + separator)))
+    matcher = re.compile(r'\s*{}\s*{}'.format(re.escape(k), separator))
+    cmatcher = re.compile(r'\s*{}\s*{}\s*{}'.format(comment,
+                                                    re.escape(k), separator))
     for line in lines:
         if matcher.match(line):
             found = True