Revert "net: Use samba default command line arguments."

Revert "net: Use samba default command line arguments."

This reverts commit c039bc15ba597d955d0ccbf5642388b0a03ba40b and dependent
commits 33c6ba805756739b7b4395bedb66ae00797cbcb1 and
        ce18ba7e24b5578672d2f2ffaab97ef708421067.

While it certainly would be a nice to have feature, this has caused more
hassle than reasonable, e.g. in net commands that need to use the machine
account like net (ads|rpc) testjoin.

This un-fixes bug #6305.
(cherry picked from commit eadbd85b2797683b3a17a1919c4aea28d6519a01)