GNUTranslations._parse(): Initialize local variable k so that if the

first line of a header section isn't an RFC-ish header, it's just
ignored instead of throwing an UnboundLocalError.

Backport candidate.

Lib/gettext.py

@@ -261,7 +261,7 @@ class GNUTranslations(NullTranslations):
             # See if we're looking at GNU .mo conventions for metadata
             if mlen == 0:
                 # Catalog description
-                lastk = None
+                lastk = k = None
                 for item in tmsg.splitlines():
                     item = item.strip()
                     if not item: