Apply CROWBAR_FIX_RAPID_CROWBAR to knife (#251)

This will apply the crowbar swing delay fix to the knife, preventing rapid melee.

dlls/gearbox/knife.cpp

@@ -228,7 +228,12 @@ int CKnife::Swing(int fFirst)
 				}
 				m_pPlayer->m_iWeaponVolume = KNIFE_BODYHIT_VOLUME;
 				if (!pEntity->IsAlive())
+				{
+#if CROWBAR_FIX_RAPID_CROWBAR
+					m_flNextPrimaryAttack = GetNextAttackDelay(0.25);
+#endif
 					return TRUE;
+				}
 				else
 					flVol = 0.1;