Produce a useful error message for NoUniqueMatch

Most of the CLIs use a NoUniqueMatch, so produce a useful
error message if that happens.  Added some tests for
find_resource as well.

Change-Id: I85ba61d5f6d1be5bd336a1cc4b02501492905f33
Closes-Bug: #1293846
Correct display of project/tenant id on display of credentials

This change corrects the display of ec2 credentails within the
ListEC2Creds method. Added explicit headers and corrected data listt o
specify tenant_id instead of project id.

Change-Id: I2ea579082bee800d774f202bdc38e2d546e57e77
Closes-Bug: #1292337
Merge "Correct display of project/tenant id on display of credentials"