ArgsManager: drop m_negated_args

When a -nofoo option is seen, instead of adding it to a separate
set of negated args, set the arg as being an empty vector of strings.

This changes the behaviour in some ways:
 - -nofoo=0 still sets foo=1 but no longer treats it as a negated arg
 - -nofoo=1 -foo=2 has GetArgs() return [2] rather than [2,0]
 - "foo=2 \n -nofoo=1" in a config file no longer returns [2,0], just [0]
 - GetArgs returns an empty vector for negated args

0 files changed, 0 insertions, 0 deletions