Revert "Only pass strings to mysqli::real_escape_string"

hhvm already has a patch in master for fixing this, making the workaround unnecessary

This reverts commit de808f57a90c9c6f7bc4dbc4e4b544a07e0daa0f.

Change-Id: I504e5bd5025ec12430ce670e05da0158b06822c9
Merge "Revert "Only pass strings to mysqli::real_escape_string""