caches: invalidate store caches when lock is taken

The fncache was not being properly invalidated each time the lock was taken, so
in theory it could contain old data from prior to the caller having the lock.
This changes it to be invalidated as soon as the lock is taken (same as all our
other caches).

mercurial/localrepo.py

@@ -996,6 +996,7 b' class localrepository(object):'
             except AttributeError:
                 pass
         self.invalidatecaches()
+        self.store.invalidatecaches()
 
     def invalidateall(self):
         '''Fully invalidates both store and non-store parts, causing the

mercurial/store.py

@@ -340,6 +340,9 b' class basicstore(object):'
     def write(self, tr):
         pass
 
+    def invalidatecaches(self):
+        pass
+
     def __contains__(self, path):
         '''Checks if the store contains path'''
         path = "/".join(("data", path))
@@ -489,6 +492,9 b' class fncachestore(basicstore):'
     def write(self, tr):
         self.fncache.write(tr)
 
+    def invalidatecaches(self):
+        self.fncache.entries = None
+
     def _exists(self, f):
         ef = self.encode(f)
         try: