Perhaps it's just a temporary glitch when a new dependency becomes available and is not yet used? There was a related error with the name of the driver deployed as a jar but I don't think it affected 7.1.1.
You first start JBoss AS7 with config as as shown above and then deploy ojdbc6.jar by copying it to the $JBOSS_HOME/standalone/deployments?
Then this is normal. Standalone.xml is referencing a datasource not yet available.
If if this shown after stop and during the new again, I think JBoss should not show these messages, may be it's just a problem of deployment order.
I remember such that I saw such messages too.
But now I have my datasources defined not in standalone.xml itself but in -ds.xml files like with server version before.
And at least 7.2.0 does not show such mesages then.
Let me remark that -ds.xml has some limitation, and the main one is that DSes defined this way is not maneageable. The most correct approach is to deploy driver as module and define driver and DSes in standalone.xml.
Note also that defining driver in standalone make it maneageable too and moreover it could be define more option there (the most important one is xa-datasource-class definition at driver level instead of define it in every DSes).
Your approach is not wrong, but you are accepting limitation and making DSes definition more complex (you need 2 deploy instead of a centralized configuration) especially if you swith to domain mode.
Just a precisation to give you the full context, hoping it could be useful