Insert third_party in to the beginning of PATH

This allows to avoid conflicts with libraries in users' PATH

R=pgervais@chromium.org, tandrii@chromium.org

Review URL: https://codereview.chromium.org/1161803004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295497 0039d316-1c4b-4281-b951-d872f2087c98

commit_queue.py

@@ -23,7 +23,7 @@ import fix_encoding
 import rietveld
 
 THIRD_PARTY_DIR = os.path.join(os.path.dirname(__file__), 'third_party')
-sys.path.append(THIRD_PARTY_DIR)
+sys.path.insert(0, THIRD_PARTY_DIR)
 
 from cq_client import cq_pb2
 from google.protobuf import text_format

third_party/google/protobuf/README.chromium

+This directory contains google.protobuf module version 2.6.0 build 0.