BUG/MINOR: mworker-prog: don't warn about deprecated section with expose-deprecated...

BUG/MINOR: mworker-prog: don't warn about deprecated section with expose-deprecated-directives

As master parses now expose-deprecated-directives option, let's emit warning
about deprecated 'progam' section only in case, if this option wasn't set in
the 'global' section. This allows to people, who don't prefer to remove the
'program' section immediately to continue to start the process in zero-warning
mode.

Adjust the warning message accordingly and mcli_start_progs.vtc test. As
expose-deprecated-directives option is a 'global' section keyword, this section
must always precede any 'program' section, if users still continue to keep
'program' section.

This doesn't need to be backported, as related to the latest changes in
the master-worker architecture.