Replacing variable logger on LOG

Commit https://review.openstack.org/#/c/94255/1 introduces check for
translating log messages. This check uses in pattern name 'LOG', so in
heat code also should be used this name intead of 'logger'. Also same
name is used in other projects.

Change-Id: Iba24c7eb1c13e68a91d090d7bcdbcb40d6e16071
Partial-Bug: #1321283
Sync version of sphinx from requirements

This allows the xml builder to be invoked, which is only
available in sphinx 1.2

Change-Id: Ide5cc535d9f087a7674a90a45445eb7e6009f35a
Merge "Sync version of sphinx from requirements"
Merge "Replacing variable logger on LOG"