Add project=skiacommon to codereview.settings

In preparation for turning on a new CQ instance for this repository.

BUG=skia:2682

Review URL: https://codereview.chromium.org/458743003

codereview.settings

diff --git a/codereview.settings b/codereview.settings
index 103cbbc..3a70653 100644
--- a/codereview.settings
+++ b/codereview.settings
@@ -4,3 +4,4 @@
 CC_LIST: reviews@skia.org
 BUG_PREFIX: skia:
 TRYSERVER_SVN_URL: https://skia-try.googlecode.com/svn
+PROJECT: skiacommon