Update acism_create.c

Update acism_create.c

Passing one pointer into realloc() and assigning the result directly into that same pointer variable can cause a memory leak if the reallocation fails, because the original allocation will still exist. The correct way to do this is to use a temporary pointer variable.

Credit: http://stackoverflow.com/a/11548901

Found by https://github.com/bryongloden/cppcheck