orangefs: Don't pollute global namespace

Prefix public functions with "orangefs_" do don't
pollute the global namespace.

This fixes a build issue on UML which also has block_signals().

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>