linux: fix a warning in the process_util unittest
linux: fix a warning in the process_util unittest

Original review: http://codereview.chromium.org/422003

BUG=none
TEST=compiles on gcc 4.4

Review URL: http://codereview.chromium.org/431034

git-svn-id: http://src.chromium.org/svn/trunk/src@32972 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 4a4cebe1b6dbee0abc461a31f6dd9728e19e49f5
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