Revert "get libbxerces-c2-dev xenial bionic docker images."

This reverts commit 351dc685.

The story here:
The DOOCS_ttf2xmllib project uses obsoleted functionality from
libxerces-c2-dev. It should be possible to replace this code with
features from libxerces-c-dev. However ttf2xmllib makes use of
BOTH libxerces-c2-dev and libxerces-c-dev. (which I am guessing is
unnessary)

libbxerces-c2-dev is not distributed on Xenial (this was a 14.04
package). On Xenial this package is replaced by libbxerces-c-dev.

libxerces-c2-dev has been backported and made available on desy Xenial
installations through the doocs-pkgs repo.

dockerfiles/bionic.docker

@@ -33,7 +33,6 @@ RUN apt-get update && \
     apt-get install -y vim-common && \
     apt-get install -y netcat-openbsd && \
     apt-get install -y libxerces-c-dev && \
-    apt-get install -y libxerces-c2-dev && \
     useradd -u 30996 msk_jenkins && \
     ln -sfn /usr/lib/x86_64-linux-gnu/libzmq.so.5 /usr/lib/x86_64-linux-gnu/libzmq.so.3
 

dockerfiles/xenial.docker

@@ -34,7 +34,6 @@ RUN apt-get update && \
     apt-get install -y vim-common && \
     apt-get install -y netcat-openbsd && \
     apt-get install -y libxerces-c-dev && \
-    apt-get install -y libxerces-c2-dev && \
     useradd -u 30996 msk_jenkins && \
     ln -sfn /usr/lib/x86_64-linux-gnu/libzmq.so.5 /usr/lib/x86_64-linux-gnu/libzmq.so.3