BUG/MEDIUM: pattern: a typo breaks automatic acl/map numbering

Dmitry Sivachenko reported that nice warning :
src/pattern.c:2243:43: warning: if statement has empty body [-Wempty-body]
                                if (&ref2->list == &pattern_reference);
                                                                      ^
src/pattern.c:2243:43: note: put the semicolon on a separate line to silence
      this warning

It was merged as is with the code from commit af5a29d ("MINOR: pattern:
Each pattern is identified by unique id").

So it looks like we can reassign an ID which is still in use because of
this.
diff --git a/src/pattern.c b/src/pattern.c
index 16aa09f..5ebb5ce 100644
--- a/src/pattern.c
+++ b/src/pattern.c
@@ -2240,7 +2240,7 @@
 						break;
 					}
 				}
-				if (&ref2->list == &pattern_reference);
+				if (&ref2->list == &pattern_reference)
 					break;
 			}