This patch addresses JIRA DTACLOUD-398 https://issues.apache.org/jira/browse/DTACLOUD-398
Problem: Sinatra's "error do" clause drops non-500 errors, ignoring those defined/raised by deltacloud. Solution: Explicitely specify non-500 errors defined/raised by deltacloud to Sinatra. Testing: To test this I temporarily modified server/lib/deltacloud/drivers/exceptions.rb changing the 409 code to each of the codes in question and then forcing the resource conflict error.
