Fixing minidump_dump to handle nacl dumps.

Fixing minidump_dump to handle nacl dumps.

Since nacl was not listed in decoding the code identifier, minidump_dump
produces errors like this (and non-zero return code):
2013-09-05 13:41:04: minidump.cc:2044: ERROR: MinidumpModule code_identifier
requires known platform, found 0x8205

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3424
TEST=tested with minidumps from nacl locally
R=mark@chromium.org,mseaborn@chromium.org

Committed: https://code.google.com/p/google-breakpad/source/detail?r=1211

[bradnelson]

Committed patchset #2 manually as r1211 (presubmit successful).

[Mark Mentovai]

LGTM again (I originally reviewed this at https://breakpad.appspot.com/626002/)