Fix logic error in gvinum's gv_set_sd_state()

[dim]

Summary

With clang 4.0.0, I'm getting the following warnings:

sys/geom/vinum/geom_vinum_state.c:186:7: error: logical not is only applied to the left hand side of this bitwise operator [-Werror,-Wlogical-not-parentheses]
                if (!flags & GV_SETSTATE_FORCE)
                    ^      ~
sys/geom/vinum/geom_vinum_state.c:186:7: note: add parentheses after the '!' to evaluate the bitwise operator first
                if (!flags & GV_SETSTATE_FORCE)
                    ^
                     (                        )
sys/geom/vinum/geom_vinum_state.c:186:7: note: add parentheses around left hand side expression to silence this warning
                if (!flags & GV_SETSTATE_FORCE)
                    ^
                    (     )

The logical not operator should obiously be called after masking.

[mav]

I doubt anybody knows this code enough, but it seems logical.

[pfg]

Nice catch, Coverity missed it completely.

[• hselasky]

I know too little of this code to comment.