cfe warning for RewriteBlocks.cpp

Saw this one today:

RewriteBlocks.cpp: In member function ‘std::string<unnamed>::RewriteBlocks::SynthesizeBlockCall(clang::CallExpr*)’:
RewriteBlocks.cpp:683: warning: ‘CPT’ may be used uninitialized in this function
RewriteBlocks.cpp:682: warning: ‘closureName’ may be used uninitialized in this function