checkpatch: Fix matching on C filenames.

Most of the prerequisite checks so far matched on filenames that ended
in some character followed by 'c' or 'h', rather than a filename that
ends in '.c' or '.h'. Fix this.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>

utilities/checkpatch.py

@@ -223,17 +223,17 @@ def is_comment_line(line):
      'check': lambda x: trailing_whitespace_or_crlf(x),
      'print': lambda: print_warning("Line has trailing whitespace")},
 
-    {'regex': '(.c|.h)(.in)?$', 'match_name': None,
+    {'regex': '(\.c|\.h)(\.in)?$', 'match_name': None,
      'prereq': lambda x: not is_comment_line(x),
      'check': lambda x: not if_and_for_whitespace_checks(x),
      'print': lambda: print_error("Improper whitespace around control block")},
 
-    {'regex': '(.c|.h)(.in)?$', 'match_name': None,
+    {'regex': '(\.c|\.h)(\.in)?$', 'match_name': None,
      'prereq': lambda x: not is_comment_line(x),
      'check': lambda x: not if_and_for_end_with_bracket_check(x),
      'print': lambda: print_error("Inappropriate bracing around statement")},
 
-    {'regex': '(.c|.h)(.in)?$', 'match_name': None,
+    {'regex': '(\.c|\.h)(\.in)?$', 'match_name': None,
      'prereq': lambda x: not is_comment_line(x),
      'check': lambda x: pointer_whitespace_check(x),
      'print':
@@ -267,7 +267,7 @@ def regex_error_factory(description):
         ('error', 'Use ovs_error() in place of error()'),
 ]
 checks += [
-    {'regex': '(.c|.h)(.in)?$',
+    {'regex': '(\.c|\.h)(\.in)?$',
      'match_name': None,
      'prereq': lambda x: not is_comment_line(x),
      'check': regex_function_factory(function_name),