Uninitialized collator is recoverable error

Summary: PHP 5.6 has made an unitialized collator a `catchable fatal error` instead of a `fatal error` that is unrecoverable.

Change our implementation to allow this. I tried to match the return values of PHP 5.6 if we run into a recoverable error

Reviewed By: @ptarjan

Differential Revision: D1620402
KernelVersion supports more version formats

Summary: This doesn't handle every possible case, but should handle most common cases. We can prevent more crashes like occurred in #3513

Fixes #3979

Reviewed By: @ptarjan

Differential Revision: D1617809