Optimize String appends in hudson.Functions

(Stapler 1.218 rejects it, I think correctly.)

Close JarFile resources in PluginWrapper and UpdateCenter

debian: Fill in gecos field for jenkins user

[JENKINS-17248] Be robust against exceptions in ItemListener.onLoaded, since this could interrupt Jenkins startup.

Thanks

The translation was too literal: the log is not full as in a cup of water (this is what "cheio" means), it is full because it is not a partial object.

If JenkinsLocationConfiguration.jenkinsUrl is still null, CoreEnvironmentContributor will silently skip several variables.
No obvious fix for that, but at least document it so it is not so surprising.

Need to restore the owner of the describable list so that changes in subsequent sessions will be persisted.
(Issue not reproduced here, but was in similar ArtifactManagerConfiguration: 757fe084.)