1165355 - Add a sanitize_checksum_type function.

https://bugzilla.redhat.com/show_bug.cgi?id=1165355
Merge branch '2.4-testing' into 2.4-dev
Merge branch '2.4-dev' into 2.5-testing
Automatic commit of package [pulp] release [2.4.4-0.1.beta].
Automatic commit of package [pulp-nodes] release [2.4.4-0.1.beta].
Merge branch '2.4-testing' into 2.4-dev
Merge branch '2.4-dev' into 2.5-testing

Conflicts:
	nodes/pulp-nodes.spec
	pulp.spec
	rel-eng/packages/pulp
	rel-eng/packages/pulp-nodes
Remove client unittest dependency on NamedTuple
Automatic commit of package [pulp] release [2.5.1-0.1.beta].
Automatic commit of package [pulp-nodes] release [2.5.1-0.1.beta].
Merge branch 'jenkins-namedtuple' into 2.5-testing
Performing a mongo $set: {} will fail on mongo 2.6+: https://jira.mongodb.org/browse/SERVER-12266