Fix recent content arch changeset to work on Oracle.
Add missing capability indexes/fkeys for Oracle.

Several changesets in 20130425102131-distributor-capabilities.xml were
postgresql specific, but were partially relevant to Oracle.

It appears the indexes however were already present, so these are
omitted in the Oracle specific versions.
Merge pull request #289 from candlepin/dgoodwin/oracle-fixes

Dgoodwin/oracle fixes