1. Fix https://issues.jenkins-ci.org/browse/JENKINS-23348 - selenium configuration under jenkins 'manager jenkins' is not saved.
2. Remove deprecated and unused parameters from Configure System page:   -rcDebug, -rcLog
3. Add parameter -browserTimeout
4. Set correct description for parameter -timeout (it was changed since selenium  v2.21)
5. Remove code which terminates starting selenium node in #startSeleniumNode() in case getHostName() returns null. Reason: node hostname can be manually configured on node in case it is non-discoverable from master. In such case node will successfully starts.
fix