R1:7451c1f6c94f

Support NO_BACKSLASH_ESCAPES in escapeStringForLikeClause()

Summary: Also simplify this clunky code.

Test Plan: /owners/view/search/?name=%25

Reviewers: epriestley

Reviewed By: epriestley

CC: aran

Differential Revision: https://secure.phabricator.com/D2114