[docker-ptf]replace ping utility from inetutils-ping to iputils-ping (#523)

* replace ping utility from inetutil-ping to iputils-ping

* fix dup typo

* change from package installing to using apt install

* remove unnecessary package handling line

dockers/docker-ptf/Dockerfile.j2

@@ -40,7 +40,9 @@ RUN sed --in-place 's/httpredir.debian.org/debian-archive.trafficmanager.net/' /
         wget                \
         cmake               \
         libqt5core5a        \
-        libqt5network5
+        libqt5network5      \
+        iputils-ping
+
 
 RUN dpkg -i \
 {% for deb in docker_ptf_debs.split(' ') -%}