Remove the now dead StringBase.cpp
Remove the now dead StringBase.cpp

Summary: The empty file was left to stop the bleeding without breaking things. Time to remove it.

Reviewed By: mzlee

Differential Revision: D5354310

fbshipit-source-id: cd3039811cf9d7371578e4078cd7d32e3bc6d8a1

facebook/folly,facebook/folly,rklabs/folly,facebook/folly,Orvid/folly,Orvid/folly,facebook/folly,Orvid/folly,rklabs/folly,Orvid/folly,Orvid/folly,rklabs/folly,facebook/folly,rklabs/folly,rklabs/folly