debian: Use a configurable group for the Jenkins user

Typical Debian practice is to have one equally-named group per system
user.  Make that for the jenkins user by default, but allow it to be
overridden in /etc/default/jenkins, same as for the user name.
Update jenkins.init.in

$time removed from Required-Start and Required-Stop
This prevents properly register the jenkis service and jenkins will not starts at boot.
$time (boot.clock) start just on runlevel B and S, but not at runlevel 3 and 5 as jenkins do.
It was also redundant to Shoul-Start and Should-Stop.
Same modification is applied also on OpenSuseBuildService.
[FIXED JENKINS-21818] Only show fingerprint links if any exist.
Different name from the main view tab bar.

This setting applies to My View's tab bar.
[JENKINS-13035] Changed the field name.

Now it gets the right property. The dropdown shows the values
for MyViewsTabBar extension
and there is help icon and text.
[JENKINS-13035] Only show this option when more than 1
MyViewTabBar available.
Force httpclient to use a new protocol socket factory which does not
explicitly bind to the client side interface.
[JENKINS-21932] Added tests to reproduce JENKINS-21932, Future#get does not abort even when a task in the queue is canceled.
[JENKINS-21932] Make the slave used in the test offline explicitly.
[FIXED JENKINS-21932] Call Item#cancel when a task in a queue is cancelled.
[FIXED JENKINS-20245]
Incorporated Nicolas' https://github.com/jenkinsci/winstone/pull/13
Merge pull request #1186 from daniel-beck/JENKINS-20245

[FIXED JENKINS-20245]
Merge pull request #1122
Merge pull request #1130 from peter-kutak/patch-1

Update jenkins.init.in
[JENKINS-21818] Merge pull request #1131
Merge branch 'master' of github.com:jenkinsci/jenkins
Merge pull request #1134 from bparees/master

Force httpclient to use a new protocol socket factory which does not explicitly bind to the client side interface.
[FIXED JENKINS-13035] Merge pull request #1141
Merge branch 'master' of github.com:jenkinsci/jenkins