fix(test): using older version of iperf2 for lte feMBMS RF-sim test

iperf2 2.0.13, used in Ubuntu 20, does not need a "back channel"; we can
therefore use it in feMBMS (which does a broadcast, without back
channel). Ubuntu 22 comes with 2.1.5, which seems to require a back
channel, or at least, we cannot use it reliably in feMBMS. Hence,
downgrade to older iperf2 version.
Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

docker/Dockerfile.eNB.ubuntu22

@@ -56,7 +56,7 @@ RUN apt-get update && \
         libconfig9 \
         openssl \
         net-tools \
-        iperf \
+        wget \
         iperf3 \
         iputils-ping \
         iproute2 \
@@ -65,6 +65,13 @@ RUN apt-get update && \
         python3-six \
         python3-requests \
         libusb-1.0-0 && \
+# Installing older version of iperf2 for feMBMS test
+    wget --quiet http://fr.archive.ubuntu.com/ubuntu/pool/universe/i/iperf/iperf_2.0.13+dfsg1-1build1_amd64.deb && \
+    dpkg -i iperf_2.0.13+dfsg1-1build1_amd64.deb && \
+# iperf --version returns 1 that fails docker build
+    iperf --version || true && \
+    rm -f iperf_2.0.13+dfsg1-1build1_amd64.deb && \
+    apt-get remove -y wget && \
 # if the --sanitize option was used to build, additional packages are required
     /bin/bash -c 'if [[ "$BUILD_OPTION" = "--sanitize" ]]; then DEBIAN_FRONTEND=noninteractive apt-get install --yes \
         #libasan5 \ # see below

docker/Dockerfile.lteUE.ubuntu22

@@ -64,7 +64,14 @@ RUN apt-get update && \
         iputils-ping \
         iproute2 \
         iperf3 \
-        iperf && \
+        wget && \
+# Installing older version of iperf2 for feMBMS test
+    wget --quiet http://fr.archive.ubuntu.com/ubuntu/pool/universe/i/iperf/iperf_2.0.13+dfsg1-1build1_amd64.deb && \
+    dpkg -i iperf_2.0.13+dfsg1-1build1_amd64.deb && \
+# iperf --version returns 1 that fails docker build
+    iperf --version || true && \
+    rm -f iperf_2.0.13+dfsg1-1build1_amd64.deb && \
+    apt-get remove -y wget && \
 # if the --sanitize option was used to build, additional packages are required
     /bin/bash -c 'if [[ "$BUILD_OPTION" = "--sanitize" ]]; then DEBIAN_FRONTEND=noninteractive apt-get install --yes \
         #libasan5 \ # see below