Ambient Generic entity fixed (for Underhell mod)

This fixes the Ambient Generic stop and toggle methods to stop and toggle a non-looping sound.


This online guide:https://developer.valvesoftware.com/wiki/Ambient_generic:_stop_and_toggle_fix


did not work correctly until I notted (! operator) m_fLooping in the if statement.


Shooting the white block toggles the sound and shooting the other block stops the sound.