if a collection has no name, use a UUID on import

Fixes #1100838, some SUSE repositories don't have that name element.
Updates for 2.5.1 becoming 2.6.0
Merge pull request #598 from bmbouter/updates-for-2-6-release-stream

Updates for 2.5.1 becoming 2.6.0
Merge branch 'bz_1100838' of github.com:ATIX-AG/pulp_rpm into ATIX-AG-bz_1100838
Adding 2.5.0 release notes
Merge pull request #599 from mhrivnak/release-notes

Adding 2.5.0 release notes
Merge branch 'release-notes' into 2.6-dev

Conflicts:
	docs/user-guide/release-notes/2.5.x.rst
Automatic commit of package [pulp-rpm] release [2.6.0-0.1.alpha].
Adds troublesooting section, and adds release notes to index
Merge pull request #600 from bmbouter/2.5-release-note-fixes

Adds troublesooting section, and adds release notes to index
Merge branch '2.5-release' into 2.6-dev
Automatic commit of package [pulp-rpm] release [2.5.0-1].
Merge branch '2.5-release' of github.com:pulp/pulp_rpm into 2.5-release
fix merge conflicts in changelog
972880 - The ISO importer now checks all ISO units before downloading
new content.

Before, it only checked the repository it was importing to, causing it
to redownload units that already existed in Pulp.