Add tips for running CI on its own from omnibus
Don't disable redis because of gitlab-rails

Because we do not have a way yet to disable gitlab-rails completely,
'gitlab-ctl reconfigure' will run migrations on gitlab-rails, and
consequently it tries to clear the cache. At that point you get an error
if Redis is not running.
Enable Sidekiq MemoryKiller by default
Change runit recipe to systemd for Fedora.

Fedora is not supported anyway, so it will not break any supported
installation.

SystemD is a better default for fedora, as fedore is using SystemD
for a few releases already. No fedora server without SystemD should
still be in production.

Closes #365
Add krb5 software definition.
Build the krb5 lib and its dependency byacc.
Use the correct order for build, don't use deprecated methods.
Pass healthcheck by disabling optional keyutils dependency.
Add byacc as a builder dependency to documentation.
Merge branch 'enable_sidekiq_memory_killer' into 'master'

Enable Sidekiq MemoryKiller by default

We have been using the Sidekiq MemoryKiller on gitlab.com since
2014-12-08, and the specific limit value of 1,000,000 since 2014-12-11.
Sidekiq memory behavior is acceptable now so I think we should ship
7.6 with the MemoryKiller enabled.

See merge request !267
Merge branch 'master' into 'master'

Use SystemD on Fedora

Fedora is not supported anyway, so it will not break any supported
installation.

SystemD is a better default for fedora, as fedore is using SystemD
for a few releases already. No fedora server without SystemD should
still be in production.

Fixes #365

See merge request !268
Merge branch 'standalone-ci-tips' into 'master'

Standalone CI tips

Some things we learned from setting up ci.gitlab.com.

See merge request !265
Merge branch 'kerberos_dependency' into 'master'

Kerberos dependency

See merge request !269
Merge branch 'master' of github.com:gitlabhq/omnibus-gitlab