Set virtual memory ulimit in package smoke testing for mongo shell tests

On SUSE 11 t1.micro AWS instances, the virtual memory ulimit is set low enough to cause the mongo shell to fail to start because it cannot allocate enough memory after SERVER-28400.

mmap(0xd161c75a000, 671088640, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)