Remove excessive path checking so we can fallback on native library search path on linux.
Remove excessive path checking so we can fallback on native library search path on linux.

LoadNativeLibrary falls back to dlopen() on linux, which will default to
searching the system library directories (/lib, /usr/lib, and those specified
in /etc/ld.so.conf) if it is given a filename w/o an absolute path.

This explicit file existance check effectively disables the search behavior.
Removing it should be okay since dlopen is designed to handle invalid paths.

BUG=None
TEST=A/B tested with only having the libraries and /usr/lib, and seeing if the "Failed to load NSS libraries" shows with and w/o the fix.

Review URL: http://codereview.chromium.org/6824013

git-svn-id: http://src.chromium.org/svn/trunk/src@80997 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 8f3571538c692e9c55da93f852065a8b7ff32892
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