Only accept actions without File::SEPARATOR in the name.

This will avoid directory traversal in implicit render.

Fixes: CVE-2014-0130
Preparing for 3.2.18 release
Fix broken tests of the previous release
Merge branch '3-2-sec' into 3-2-stable

Conflicts:
	actionpack/CHANGELOG.md
use fnmatch to test for case insensitive file systems

this is due to:

  https://bugs.ruby-lang.org/issues/5994
feature detect for FNM_EXTGLOB for older Ruby. Fixes #15053
Merge branch '3-2-stable' of https://github.com/rails/rails into 3-2-fixes