subrepo: ensure "lock.release()" execution at the end of "_cachestorehash()"

Before this patch, "lock.release()" for "self._repo" in
"_cachestorehash()" of "hgsubrepo" may not be executed, if unexpected
exception is raised, because it isn't executed in "finally" clause.

This patch ensures "lock.release()" execution at the end of
"_cachestorehash()" by moving it into "finally" clause.

mercurial/subrepo.py

@@ -586,6 +586,7 b' class hgsubrepo(abstractsubrepo):'
         '''
         cachefile = self._getstorehashcachepath(remotepath)
         lock = self._repo.lock()
+        try:
         storehash = list(self._calcstorehash(remotepath))
         cachedir = os.path.dirname(cachefile)
         if not os.path.exists(cachedir):
@@ -593,6 +594,7 b' class hgsubrepo(abstractsubrepo):'
         fd = open(cachefile, 'w')
         fd.writelines(storehash)
         fd.close()
+        finally:
         lock.release()
 
     @annotatesubrepoerror