fix B15007 - boomerangs used hand-to-hand

fix B15007 - boomerangs used hand-to-hand

     Hitting with a wielded boomerang was supposed to have a chance to
break it, but the code was located in a spot that would never be reached
when bashing with a missile weapon.  Also, its rnl() usage would have
made the bad effect--losing your weapon--be more likely to occur when
you had good luck and less likely when you had bad luck.  And it wasn't
setting `unweapon', so you wouldn't have gotten a bashing with barehands
message on the next attack after the weapon had been destroyed.