Fixing a clang warning.
Fixing a clang warning.

This is a followup change from https://breakpad.appspot.com/569002/

This prevents push_back from ever calling Realloc()
with 0 (which could happen if wasteful_vector was
constructed with size_hint set to 0, causing
allocated_ to be 0.
Review URL: https://breakpad.appspot.com/576002

git-svn-id: 7939527bf0a06ad24ad020f729d5600cb42ed5d7@1166 4c0a9323-5329-0410-9bdc-e9ce6186880e

bittorrent/breakpad,wesen/google-breakpad,wesen/google-breakpad,wesen/google-breakpad,wesen/google-breakpad,bittorrent/breakpad,bittorrent/breakpad,bittorrent/breakpad,bittorrent/breakpad,wesen/google-breakpad,bittorrent/breakpad,bittorrent/breakpad,wesen/google-breakpad