UTILS: point to right JDK when generating javadoc

- When generating javadoc for RPC API use custom installation of JDK
Merge pull request #401 from zlamalp/rpc-javadoc

UTILS: point to right JDK when generating javadoc
Add rights for engine to call getAssignedServices

Engine/dispatcher needs this method for resolving ExecService-Facilty
pairs from audit message.
Fix permissions check in services

If target file is symlink, permissions is checked on linked file (not on
symlink itself)

Affected services: fs_home, k5login and passwd_scp