Fix #641 - mock configuration is hardcoded

conf/mock.cfg

@@ -0,0 +1,14 @@
+config_opts['root'] = '$root'
+config_opts['target_arch'] = '$arch'
+config_opts['legal_host_arches'] = ('$arch',)
+config_opts['chroot_setup_cmd'] = 'install $group'
+config_opts['dist'] = ''
+config_opts['extra_chroot_dirs'] = [ '/run/lock', ]
+config_opts['releasever'] = ''
+config_opts['package_manager'] = 'dnf'
+config_opts['nosync'] = True
+config_opts['use_bootstrap_container'] = False
+
+config_opts['yum.conf'] = \"\"\"
+$yum_conf
+\"\"\"

conf/yum.conf

@@ -0,0 +1,17 @@
+[main]
+keepcache=1
+debuglevel=2
+reposdir=/dev/null
+logfile=/var/log/yum.log
+retries=20
+obsoletes=1
+gpgcheck=0
+assumeyes=1
+syslog_ident=mock
+syslog_device=
+install_weak_deps=0
+metadata_expire=3600
+mdpolicy=group:primary
+
+# repos
+