Refactor: JJB code

- Fix shellcheck errors: SC1090, SC2164 and warnings
- Refactor yaml to standardize it across the repo with prettier
- Refactor with yamllint

Change-Id: Ie36c4a3af173fa3609cd4e904775be54b4a56990
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>
diff --git a/jjb/pti-rtp/install-yocto-prereq-centos.sh b/jjb/pti-rtp/install-yocto-prereq-centos.sh
index dc2c796..ba3feb8 100644
--- a/jjb/pti-rtp/install-yocto-prereq-centos.sh
+++ b/jjb/pti-rtp/install-yocto-prereq-centos.sh
@@ -25,10 +25,10 @@
      diffutils diffstat cpp gcc gcc-c++ glibc-devel texinfo chrpath socat \
      perl-Data-Dumper perl-Text-ParseWords perl-Thread-Queue perl-Digest-SHA \
      python3-pip xz which SDL-devel xterm"
-echo "INFO: installing epel-release and packages $pkgs"
+echo "INFO: installing epel-release and packages ${pkgs}"
 sudo yum install -y epel-release \
   && sudo yum makecache \
-  && sudo yum install -y $pkgs
+  && sudo yum install -y "${pkgs}"
 
 git config --global user.name "oran inf builder"
 git config --global user.email "oran.inf@windriver.com"