continuing failures in trunk - testAddIdentityColumn()

[mike matrigali]

I am going to let testAddIdentityColumn() continue to fail 
intermittently on trunk over the US holiday weekend (thursday-sunday). 
I am actively working on DERBY-6774, but still have not reproduced in my 
environment -
so allowing it to fail is giving me some more data points to understand
what is happening.
For now do ignore any failures in trunk for testAddIdentityColumn.

/mikem