AutoMod: fix bug with int account threshold checks

It should be valid to define a check for one of the account thresholds
similar to:

    author:
        comment_karma: 0

to check for exactly that value. However, since this is parsed in as an
int, trying to do a regex match on it (to check for the presence of an
operator - equal/greater-than/less-than sign) crashes.

This ensures that the comparison value is converted to a string so that
the rest of the code can handle it.

r2/r2/lib/automoderator.py

@@ -874,7 +874,7 @@ class RuleTarget(object):
         for threshold in thresholds:
             compare_value = getattr(self, threshold, None)
             if compare_value is not None:
-                checks[threshold] = compare_value
+                checks[threshold] = str(compare_value)
 
         # if we don't need to actually check anything, just return True
         if not checks: