Method mapping filename bug: c_str on a temp string
Method mapping filename bug: c_str on a temp string

Summary:
Our method map filenames were corrupt because we were calling c_str on
a temporary string object.  We should try really hard to ban c_str from our
code.

Reviewed By: onomatopoeia

Differential Revision: D3650634

fbshipit-source-id: cc024a85063474c9b70e0cc19fb669732c851e43

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex