Display max_template_size when a template is too large

Show the value of the 'max_template_size' configuration variable in the
error message when a user uploads a template that is larger than the
configured maximum allowed size.

Change-Id: Iaef8f0a9fd2f9df81459539226bceb9146a13f8e
Closes-Bug: #1279888
Remove spurious tracebacks from tests, part 2

Added the same fix that was applied to the other stack_delete tests in
ed7710cd3 to test_stack_delete_other_dead_engine_active_lock.

Change-Id: I3a81844bd6c21013e5956fce9ff9fe5508fcbd94
Closes-Bug: #1278836
Merge "Remove spurious tracebacks from tests, part 2"
Merge "Display max_template_size when a template is too large"