Ensure that 'castCall' is not "may be used uninitialized" in wrappers.cpp
Merge pull request #256 from vasslitvinov/coercion-wrapper-elimination-build-fix

Ensure that 'castCall' is not "may be used uninitialized" in wrappers.cpp

Vass asked me to review and merge this on his behalf.  There was a warning about a possibly uninitialized variable because of a code path with an INT_FATAL.  It is initialized to NULL in that path now.