Merge pull request #237 from ktf/master

Define a few git variables globally.
Merge pull request #238 from ktf/master

More global git parameters.
Merge pull request #239 from ktf/master

Use http to fetch cmssw sources.
Typo.
disable root6 and threaded ibs of 73x
Do not check for certificate due to missing CA on slc5
Revert change using git cms-init.

Apparently git cms-init and git cms-merge-topic do not play nicely the
one with the other, since the only reason for that was to do a local git
config (previously going to the wrong repo, BTW), I simply do a global
config and forget about it.
Unpack requests at the same level as before.
Add quotes around cmsbuild name.
Add Alessandro to request and approve build of releases
Setup IBs for CMSSW_7_4_CLANG_X
Merge pull request #240 from nclopezo/add-74-clang-ibs

Setup IBs for CMSSW_7_4_CLANG_X
Add CMSSW_7_4_0_pre1 for slc6_amd64_gcc481 as .
Setup IBs for CMSSW_7_3_DEBUG_X
Merge pull request #241 from nclopezo/add-74-debug-ibs

Setup IBs for CMSSW_7_3_DEBUG_X
Add CMSSW_7_4_0_pre1 for slc6_amd64_gcc491 as .
Use full hostname for the time being.

We should really use http for this.
Add CMSSW_6_2_0_SLHC21 for slc6_amd64_gcc472 as .
Automated builds -- Allow to abort the build of a release:
  - The abort can be done when the status is build-in-progress,
    and no architecture is being uploaded or is already uploaded.
  - It removes the release in github and the tag in cmssw.
  - It removes the tags in cmsdist that could have been created.
  - After aborting, the new status of the issue is build-aborted.
    The user should create a new issue to start over.
Merge pull request #242 from nclopezo/allow-abort-builds

Automated builds -- Allow to abort the build of a release: