rule-syntax-check: allow commas inside quoted strings

Using a regex to match the groups is smarter than the split(',') that
would break in those cases.

Tested:

  SUBSYSTEM=="usb", ENV{ID_USB_INTERFACES}=="*:060101:*,*:070202:*", TAG+="uaccess"

Rule checker doesn't break there after this commit.
diff --git a/test/rule-syntax-check.py b/test/rule-syntax-check.py
index 1a58d17..7ee34eb 100755
--- a/test/rule-syntax-check.py
+++ b/test/rule-syntax-check.py
@@ -33,6 +33,8 @@
 args_tests = re.compile(r'(ATTRS?|ENV|TEST){([a-zA-Z0-9/_.*%-]+)}\s*(?:=|!)=\s*' + quoted_string_re + '$')
 no_args_assign = re.compile(r'(NAME|SYMLINK|OWNER|GROUP|MODE|TAG|RUN|LABEL|GOTO|OPTIONS|IMPORT)\s*(?:\+=|:=|=)\s*' + quoted_string_re + '$')
 args_assign = re.compile(r'(ATTR|ENV|IMPORT|RUN){([a-zA-Z0-9/_.*%-]+)}\s*(=|\+=)\s*' + quoted_string_re + '$')
+# Find comma-separated groups, but allow commas that are inside quoted strings.
+comma_separated_group_re = re.compile(r'(?:[^,"]|' + quoted_string_re + ')+')
 
 result = 0
 buffer = ''
@@ -57,8 +59,8 @@
 
         # Separator ',' is normally optional but we make it mandatory here as
         # it generally improves the readability of the rules.
-        for clause in line.split(','):
-            clause = clause.strip()
+        for clause_match in comma_separated_group_re.finditer(line):
+            clause = clause_match.group().strip()
             if not (no_args_tests.match(clause) or args_tests.match(clause) or
                     no_args_assign.match(clause) or args_assign.match(clause)):