Fix the missing health pickup sound on aerowalk.

Caused by an out-by-one error thanks to the insane way the sound list is
built. Came about when doing the model/sound list sanitation during the
GLSL project, but this one was sneakier as it resulted only in a missing
sound rather than a segfault.

qw/source/cl_parse.c

@@ -870,6 +870,7 @@ CL_ParseSoundlist (void)
 			Host_Error ("Server sent too many sound_precache");
 		strcpy (cl.sound_name[cl.numsounds], str);
 	}
+	cl.numsounds++;
 
 	n = MSG_ReadByte (net_message);