renaming discern_branch

also adding certs and discern to provision
Merge pull request #458 from edx/jarv/discern-version

renaming discern_branch
giving the web user permission to read the gnupg keys
Merge pull request #460 from edx/jarv/gpg-perms

giving the web user permission to read the gnupg keys
setting perms recursively for the gnupg dir
state=directory
turn off buffering
chgrp not done as certs user
change mode to 600
Merge pull request #461 from edx/jarv/gpg-perms

Jarv/gpg perms
gnupg dir needs to be owned by the web user

Unfortunately this is necessary since temp files are written to this dir
Merge pull request #462 from edx/jarv/gpg-perms

gnupg dir needs to be owned by the web user
Skip gather assets in devstack
Disabled mongo journaling for devstack and Jenkins
Removed old browsers task from jenkins_worker
changing null to false
removing double quotes around $elb
Merge pull request #466 from edx/jarv/fix-elb-reg

Jarv/fix elb reg
Merge pull request #463 from edx/will/mongo-journal

Disable mongo journaling on devstack and Jenkins
Merge pull request #465 from edx/will/devstack-skip-assets

Skip gather assets in devstack