[docker] Add few kerberos packages in py3 Dockerfile
'krb5-config', 'krb5-user' packages were missed when the py2 and py3 Dockerfiles were swapped.
@@ -11,6 +11,8 @@ RUN apt-get update -y && apt-get install -y \
libsasl2-modules-gssapi-mit \
libsasl2-dev \
libkrb5-dev \
+ krb5-config \
+ krb5-user \
libxml2-dev \
libxslt-dev \
libmysqlclient-dev \
