Avoid user notifications when LockTimeout is received (#2900)
Avoid user notifications when LockTimeout is received (#2900)

* Avoid user notifications when LockTimeout is received

LockTimeout happens when there are more than one build trigger almost
at the same time.

* Clean up code comment

rtfd/readthedocs.org,davidfischer/readthedocs.org,pombredanne/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,rtfd/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org,safwanrahman/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org