Make authz parsing more strict, stopping once it sees characters that are
not valid directives.

* subversion/libsvn_repos/authz.c
  (authz_parse_line): Instead of doing a simple strchr to find r and w
   characters in the value use a more strict approach that stops us from
   running off into comments.

Index: subversion/libsvn_repos/authz.c
===================================================================
--- subversion/libsvn_repos/authz.c	(revision 19461)
+++ subversion/libsvn_repos/authz.c	(working copy)
@@ -186,17 +186,34 @@
         return TRUE;
     }
 
-  /* Set the access grants for the rule. */
-  if (strchr(value, 'r'))
-    b->allow |= svn_authz_read;
-  else
-    b->deny |= svn_authz_read;
+  {
+    svn_boolean_t seen_r = FALSE, seen_w = FALSE;
+    const char *itr = value;
 
-  if (strchr(value, 'w'))
-    b->allow |= svn_authz_write;
-  else
-    b->deny |= svn_authz_write;
+    while (*itr)
+      {
+        if (*itr == 'r')
+          seen_r = TRUE;
+        else if (*itr == 'w')
+          seen_w = TRUE;
+        else
+          break;
 
+        ++itr;
+      }
+
+    /* Set the access grants for the rule. */
+    if (seen_r)
+      b->allow |= svn_authz_read;
+    else
+      b->deny |= svn_authz_read;
+
+    if (seen_w)
+      b->allow |= svn_authz_write;
+    else
+      b->deny |= svn_authz_write;
+  }
+
   return TRUE;
 }