It was possible to leak some resources if initialization fails half way
through.

BUG=angleproject:2546

Change-Id: I0ea75a274fed27b118e788785bb72aff5fe8381e
Reviewed-on: https://chromium-review.googlesource.com/1070221Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>