Replace Ubuntu 18.10 with Ubuntu 19.04

Signed-off-by: Alexey Neyman <stilor@att.net>

testing/docker/ubuntu19.04/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:18.10
+FROM ubuntu:19.04
 ARG CTNG_UID
 ARG CTNG_GID
 RUN groupadd -g $CTNG_GID ctng
@@ -6,7 +6,7 @@ RUN useradd -d /home/ctng -m -g $CTNG_GID -u $CTNG_UID -s /bin/bash ctng
 RUN apt-get update
 RUN apt-get install -y gcc g++ gperf bison flex texinfo help2man make libncurses5-dev \
     python3-dev autoconf automake libtool libtool-bin gawk wget bzip2 xz-utils unzip \
-    patch libstdc++6
+    patch libstdc++6 rsync
 RUN wget -O /sbin/dumb-init https://github.com/Yelp/dumb-init/releases/download/v1.2.1/dumb-init_1.2.1_amd64
 RUN chmod a+x /sbin/dumb-init
 RUN echo 'export PATH=/opt/ctng/bin:$PATH' >> /etc/profile