No longer support installs where register_globals is enabled

register_globals has been deprecated since PHP 5.3, which was released
5 years ago. There's absolutely no reason anyone should have this turned
on, and if they do, well, they probably have bigger issues than this.

Due to changes in WebStart.php, the web installer will now fail to
start, just showing an error message stating that register_globals
must be disabled beforehand.

The command-line installer will display the
"config-register-globals-error" message before exiting.

Change-Id: If951d15293c5f6aa8a92e91fefcb00f04e6c13b3
Merge "No longer support installs where register_globals is enabled"