New pop_arg function
New pop_arg function

Pop a named argument from the args/kwargs and return a tuple consisting of the
argument value, the modified args and the modified kwargs.

Change-Id: Ie02e3024be10b2f6c081f4882c6f50c33a12e8f7
Signed-off-by: Michael Walsh <10404802c7de463f402c4a18638106ca1b12ef61@us.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation