Better handling of permission errors during install.

Error messages are now more accurate and descriptive.

BUG=155411,151684

Review URL: https://codereview.chromium.org/11115018

git-svn-id: https://nativeclient-sdk.googlecode.com/svn/trunk/src@1448 050acbb0-2703-11df-ab0a-9f3f633ae91d
1 file changed