docker pull hangs with the following message "Layer already being pulled by another client. Waiting"

Issue

*docker pull command will hang intermittently (meaning occasionally when docker pulls are run, not that one docker pull is occasionally hanging) with the following for example:

[root@sd-e6ec-7fc8 ~]# docker pull tomcat:7.0
Trying to pull repository docker.io/library/tomcat ... 7.0: Pulling from library/tomcat
6d1ae97ee388: Verifying Checksum
8b9a99209d5c: Pulling fs layer
2e05a52ffd47: Pulling fs layer
9fdaeae348bb: Pulling fs layer
67d05086af43: Pulling fs layer
2e9d1ec89d66: Pulling fs layer
1afb0d51eee0: Pulling fs layer
5cb24a57fa37: Pulling fs layer
110c2f290b04: Pulling fs layer
966dcd51a14f: Pulling fs layer
8a57ce404f1b: Pulling fs layer
e1b97b980d07: Pulling fs layer
0e74df9853d7: Pulling fs layer
20d94860039d: Verifying Checksum
ad4e266e1bd1: Pulling fs layer
13091c61ed8d: Pulling fs layer
6c6bae9ca483: Pulling fs layer
068fc2e47624: Pulling fs layer
373f6ee029ce: Layer already being pulled by another client. Waiting.