remove dead case for F_SETLKW in fcntl

the first switch already returns in the F_SETLKW code path so it need
not be handled in the second switch. moreover the code in the second
switch is wrong for the F_SETLKW command: it's not cancellable.

src/fcntl/fcntl.c

@@ -39,7 +39,6 @@ int fcntl(int fd, int cmd, ...)
 	}
 	switch (cmd) {
 	case F_SETLK:
-	case F_SETLKW:
 	case F_GETLK:
 	case F_GETOWN_EX:
 	case F_SETOWN_EX: