[VOL-5272] Check on code review input from Mirko D

[VOL-5031] - original ticket

app-install.sh
--------------
  o Fixed a typo in parsed path:
    + use names="${names[0]}" to extract path from sed command output.
    + Inline comments showing input string and names array variable.

  o Screen sources with latest shellcheck v0.9.0.
  o Replace cd $HERE && cd $APP_ROOT with {pushd,popd} and error checking.

  o Usability enhancements to improve log readability:
    + func init: validate and display envionment vars used.
    + Display banners and whitespace to breakup a long stream
      of artifact copying and unpacking.

  o Add simple getopts command line switches to enable --debug mode.

  o Replace "cp -v" with "rsync --checksum"
    + Adds error checking, detect bit flip.
    + Only copy files when needed.

Dockerfile.voltha-onos
----------------------
  o Install rsync command, mia from the base docker image.
  o Display command version installed for rsync and unzip.

Change-Id: Ief6ca6bf381394d6a50e6bb17037228a2fe2041a
diff --git a/Dockerfile.voltha-onos b/Dockerfile.voltha-onos
index 0af83e2..9c64900 100644
--- a/Dockerfile.voltha-onos
+++ b/Dockerfile.voltha-onos
@@ -74,7 +74,15 @@
 RUN apt-get install --reinstall -y ca-certificates
 RUN rm /etc/apt/sources.list.d/zulu-openjdk.list
 RUN apt-get update
-RUN apt-get install unzip -y
+
+# ----------------------------------------------------
+# [TODO] Morph into a loop: install pkg; pkg --version
+# ----------------------------------------------------
+RUN apt-get install -y rsync
+RUN apt-get install -y unzip
+
+RUN rsync --version | head -n1
+RUN unzip --help    | head -n1
 
 RUN <<BANNER
     echo ""