xrootd4j: Add back old mistyped constants for compatibility

For compatibility with old plugins we should not remove these old
mistyped constants (they were used in version 1.2.0).

Target: trunk, 1.2
Merge branch 'fix/old-constants'

Conflicts:
	xrootd4j/src/main/java/org/dcache/xrootd/protocol/XrootdProtocol.java
	xrootd4j/src/main/java/org/dcache/xrootd/util/FileStatus.java