Fixed a compile error with --enable-nvidia-gpu.
cc1plus: warnings being treated as errors
nvidia.c: In function ‘int check_nvidia_setup()’:
nvidia.c:487: error: deprecated conversion from string constant to ‘char*’
make[3]: *** [nvidia.o] Error 1
Did a typecast to char * for the constant string. TRQ-1793
Merge branch '4.2-dev' of https://github.com/adaptivecomputing/torque into 4.2-dev