test: don't fail in ioctl mock for unknown ioctl

It's not possible to run the test under gdb because in this
configuration mock calls fail for all unknown IOCTLs. As it turns, just
returning a not supported let's the test case still run under gdb.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

libnvme/test/ioctl/mock.c

@@ -157,7 +157,8 @@ int ioctl(int fd, int request, ...)
 		if (!real_ioctl)
 			fail("Error: dlsym failed to find original ioctl\n");
 #else
-		fail("Error: unhandled ioctl\n");
+		fprintf(stderr, "Warning: unhandled ioctl %lx\n", request);
+		return -ENOTTY;
 #endif
 	}