Revert "autoconf: Complain if tcmalloc is not found."
Revert "autoconf: Complain if tcmalloc is not found."

This reverts commit a9afdca18e2264fff70b5aaf864ae9abb0436dca.

This breaks debian build on lenny because tcmalloc isn't part of libgoogle-perftools-dev.

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph