@akshaybirajdar I too faced the same error, but it got resolved when I uninstalled the Postgres rpm(pgdg-redhat-repo-latest.noarch.rpm) available at /opt/ and reinstalled it from command
cd /opt/
wget https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm
yum install pgdg-redhat-repo-latest.noarch.rpm
After this run the bahmni install command and it will fail at this step
Follow this link for the solution.