selftests: net/rds: add module not found

This fix solves this error, when calling kselftest with targets "net/rds":

The error was found by running tests manually with the command:
make kselftest TARGETS="net/rds"

The patch also specifies to import ip() function from the utils module.

Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Link: https://patch.msgid.link/20241010194421.48198-1-alessandro.zanni87@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Alez87

tools/testing/selftests/net/rds/test.py

@@ -14,8 +14,11 @@
 import atexit
 from pwd import getpwuid
 from os import stat
-from lib.py import ip
 
+# Allow utils module to be imported from different directory
+this_dir = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(this_dir, "../"))
+from lib.py.utils import ip
 
 libc = ctypes.cdll.LoadLibrary('libc.so.6')
 setns = libc.setns