Fix ebs copysnapshot operation

This includes two fixes.  The actual fix is https://github.com/jamesls/botocore/commit/6683d7e9051cd849f39920766e4d1e78a2d23888.  However, as part of this test I included two integration tests that gives us greater confidence that nothing is actually broken.  In writing these tests I found a number of issues with our waiter implementation.  One which was a config issues, the other which was a bug in how we're handling incomplete waiter configs (which will eventually be fixed upstream).  The waiter fixes are in https://github.com/jamesls/botocore/commit/68a2f7b43479dc48a799178c7f2128654c6fefe3.

cc @kyleknap @danielgtaylor