Make the non-Linux platforms support an interactive opal_path_nfs() test.

On Linux, if this test is run with no command line params, it will run
"mount" and analyze the output (same as it always has).

On all platforms, if you provide one or more command line options,
each command line option is given to opal_path_nfs() and the result is
sent to stdout.
ob1 does not check the return code of mpool_register. This can cause the
ob1 dummy registration to actually be used when using udreg. Fix this by
always setting reg to NULL when mpool/udreg's register function fails.

cmr=v1.7.4:reviewer=rhc
Update Mac support for 10.8 and 10.9 - need to review about earlier versions

cmr=v1.7.4:reviewer=ompi-gk1.7