Use smaller number for upper limit of mac_user's _first_avail_uid helper function
Use smaller number for upper limit of mac_user's _first_avail_uid helper function

Using 2^32 as the upper limit causes an OverflowError when unit tests
are run on a 32-bit host. If your OS X host has over 4 billion users, I
tip my hat to you.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt