Adding extra debugging to extension docs build process.
Adding extra debugging to extension docs build process.

TEST=Path is printed if invalid zip file exists in examples directory
BUG=None

Review URL: http://codereview.chromium.org/5975005

git-svn-id: http://src.chromium.org/svn/trunk/src@70232 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 14e7fdde911676181309a8acf18e371942f06d01
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser