master: Add support for LIZ_CLTOMA_FUSE_(MKDIR|MKNOD)

Add support for these two network messages. They pass umask together with mode
to make it possible to implement default ACLs. Old packages (CLTOMA_FUSE_MK*)
are still supported and in such case the master server assumes that umask is
equal to 0.

Change-Id: I7f77d67a0d27c1302c1bae62d5e9a7af49c24c33