File reader fixes for verbs

- Fix local file reader to always read in chunks
- Have gzip stream raise an exception if the full data is requested

util/registry/gzipwrap.py

@@ -11,6 +11,9 @@ class GzipWrap(object):
     self.is_done = False
 
   def read(self, size=-1):
+    if size is None or size < 0:
+      raise Exception('Call to GzipWrap with unbound size will result in poor performance')
+
     # If the buffer already has enough bytes, then simply pop them off of
     # the beginning and return them.
     if len(self.buffer) >= size or self.is_done: