install_rally.sh: Add redhat-rpm-config to package list for EL distros
install_rally.sh: Add redhat-rpm-config to package list for EL distros

redhat-rpm-config is required when installing netifaces from pip on EL
distros such as Fedora, CentOS and RHEL.

Closes-Bug: #1528216
Change-Id: I343bde5ca13af351e5ed3f194d9318242b5ac5bf

amit0701/rally,eonpatapon/rally,yeming233/rally,openstack/rally,gluke77/rally,amit0701/rally,vganapath/rally,gluke77/rally,gluke77/rally,vganapath/rally,eonpatapon/rally,gluke77/rally,vganapath/rally,eayunstack/rally,yeming233/rally,eayunstack/rally,openstack/rally,amit0701/rally,openstack/rally,openstack/rally,vganapath/rally,eayunstack/rally