Hyperdex daemon reports IO errors if data directory is a relative path

[AaronFriel]

Using an argument such as -D ./daemons/daemon1 frequently gives me this puzzling error:

E0716 06:27:38.078249  1343 datalayer.cc:1406] IO error at the disk layer: IO error: ./daemons/daemon1/000004.log: No such file or directory

Changing the argument to this fixes it: -D $(readlink -f ./daemons/daemon1), as the relative path will be expanded.

[michelkaporin]

@AaronFriel getting the same. Thanks for sharing the fix.