You're missing the rhel-7-server-rpms repo,
which contains the base OS distribution and the perl-Date-Manip package.
What's showing in your list is just the optional packages repo. Are your
certificates and subscriptions all in order to allow Red Hat to grant your
system access?
Michael V. Pelletier
IT Program Execution
Principal Engineer
978.858.9681 (5-9681) NOTE NEW NUMBER
339.293.9149 cell
339.645.8614 fax
michael.v.pelletier@xxxxxxxxxxxx