update repo

mock-config/dev-epel-7-plus-x86_64.cfg

@@ -22,6 +22,13 @@ syslog_device=
 # repos
 [base]
 name=BaseOS
+mirrorlist=http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os
+failovermethod=priority
+gpgkey=file:///etc/pki/mock/RPM-GPG-KEY-CentOS-7
+gpgcheck=1
+
+[cern]
+name=BaseOS
 baseurl=http://linuxsoft.cern.ch//cern/centos/7/cern/x86_64
 enabled=1
 gpgcheck=0