Sets the LHM's session lock wait timeout variables

Problem:

It is possible for the atomic switch to fail when another session has acquired the meta data lock

Solution:

This is part 1 of the solution, here we are forcing the LHM's session variables to be n seconds less than the global,
the next iteration of this will make it so we retry on failure to acquire the lock.
Fail if the global timeouts are less than the delta
Merge pull request #1 from Shopify/set_lock_wait_timeout

Sets the LHM's session lock wait timeout variables