Some RPM installs fails with:

Error: nothing provides mono(System) = 2.0.0.0 needed by opendaylight-8.0.0-0.1.20170901snap214.el7.noarch
(try to add '--allowerasing' to command line to replace conflicting packages)

This only seems to happen for RPMs built on ODL infra, not RPMs built on the CentOS Community Build System. There is suspicious looking RPM repo-add configuration in the Packer build logic for the VM we use when building RPMs.

RelEng/Builder's Packer config for the java-builder VM (`packer/provision/java-builder.sh`):

# Needed for vsemprovider build in vtn project to enable C# compilation.
rpm --import "http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF"
# Add the mono tools repository
yum-config-manager -y --add-repo http://download.mono-project.com/repo/centos/
# Install the mono toolchain and nuget
yum -y install mono-complete nuget

Need to create a test to verify if a package has this dep issue or not. Then likely need to build in a mock env to isolate RPM build from underlying system better.

Imported from Trello