dcache-xrootd: Upgrade to xrootd4j 1.2.1

Target: trunk
Request: 2.6
Require-notes: no
Require-book: no
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Patch: http://rb.dcache.org/r/6192/
(cherry picked from commit d36ae0cc58c6a2cb99aa1ada3b4a04a62f07d1cc)

Conflicts:
	pom.xml
Merge pull request #264 from gbehrmann/fix/2.6/rb6192

dcache-xrootd: Upgrade to xrootd4j 1.2.1