Fix pkg-config-wrapper to forward the return value from pkg-config

BUG=None
TEST=Run ./pkg-config-wrapper /  --atleast-version=3.0 inputproto and check that it returns 1

Review URL: http://codereview.chromium.org/4900001

git-svn-id: http://src.chromium.org/svn/trunk/src/build@65956 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

linux/pkg-config-wrapper

@@ -11,4 +11,6 @@ rewrite=`dirname $0`/rewrite_dirs.py
 
 shift
 config_path=$root/usr/lib/pkgconfig:$root/usr/share/pkgconfig
-PKG_CONFIG_PATH=$config_path pkg-config --define-variable=prefix=/usr "$@" | $rewrite $root
+set -e
+result=`PKG_CONFIG_PATH=$config_path pkg-config --define-variable=prefix=/usr "$@"`
+echo "$result"| $rewrite $root