Fix the xml:base attribute of the DMR when it is read from the MDS
The xml:base attribute of the DMR must be the name of the server that transmits the response to the client. We will need to alter this once the DMR response has been read from the MDS.
This information is passed into the BES via a command from the OLFS. The MDS will need to access that information and add it to the response. The information is part of a context:
One issue is what we do when the ml:base context is not set by whatever calls the BES. Choices:
Use a default
Exception seemed like the best option, but it breaks a bunch of tests. Default also seemed sensible, but it either hardwires a response or means a trip to the conf file. Either way, it breaks the existing tests. Both of these presume that we will always have a value for xml:base that the BES should use. I decided to go with 'Nothing.' If xml:base is not set, then the response is read from the MDS and returned unchanged. If the caller wants it this way, great. If not, it's plain to see there's no xml:base present. Also, no tests break. This is not really trivial since one aspect of the MDS tests is that they use the same baselines as a parallel set of tests that don't use the MDS (two sets of drivers, one set of baselines).