Add failing test case for #9654
Reverts rendering behavior when format is unknown

If a request has unknown format (eg. /foo.bar), the renderer
fallbacks to default format.

This patch reverts Rails 3.2 behavior after c2267db commit.

Fixes issue #9654.
Return nil for Mime::NullType#ref
Fixed typo
Merge pull request #10160 from choudhuryanupam/fix_typo_n_grammar

Fixed typo
Removed unused setup
Merge pull request #10162 from choudhuryanupam/fix_activesupport_test

Removed unused setup
Using public send instead of send for the PerThreadRegistry module.
Prevents you from accidentally calling a protected method.
Merge pull request #10165 from wangjohn/public_send_for_instance

Using public send instead of send for the PerThreadRegistry module.
Searching for rails executable correctly

 * Current logic of finding Rails executable in parent directory is
   not returning full path of executable if it is found in one of the
   parent directories
 * To compensate for this, we have to call exec_app_rails recursively
   until the executable is found or we cant do 'chdir' anymore
 * This solution finds the correct executable path from parent
   directory(s) recursively