Update mininet version (#517)

* Support negative-valued action parameters
by converting them in the Python helper code into a positive value
whose bit pattern is the 2's complement representation of the negative
value.

* Update version of mininet installed to the latest available in 2023-Jun

vm-ubuntu-20.04/user-common-bootstrap.sh

@@ -4,15 +4,13 @@
 set -xe
 
 # --- Mininet --- #
-MININET_COMMIT="aa0176fce6fb718a03474f8719261b07b670d30d"  # 2022-Apr-02
+MININET_COMMIT="5b1b376336e1c6330308e64ba41baac6976b6874"  # 2023-May-28
 git clone https://github.com/mininet/mininet mininet
 cd mininet
 git checkout ${MININET_COMMIT}
 PATCH_DIR="${HOME}/patches"
-patch -p1 < "${PATCH_DIR}/mininet-dont-install-python2-2022-apr.patch" || echo "Errors while attempting to patch mininet, but continuing anyway ..."
+patch -p1 < "${PATCH_DIR}/mininet-patch-for-2023-jun.patch"
 cd ..
-# TBD: Try without installing openvswitch, i.e. no '-v' option, to see
-# if everything still works well without it.
 sudo ./mininet/util/install.sh -nw
 
 find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-7-after-mininet-install.txt