Join WFS feature source cause ServerDescribeScheme fail

[ChristineBao]

Report from Autodesk QA:

Steps:

1. Create one connection to WFS data.
   
2. Create one join with 2 feature class in this WFS feature resource.
   
3. Refresh to describe schema and feature class.
   

Results:
One error happened.
An exception occurred in FDO component. Schema cannot be found in the collection.

Expected results:
The schema and feature class info should be listed correctly.

Workaround: N

Regression: Y AIMS 2012 works well.

[ChristineBao]

This defect happens in ServerDescribeSchema.cpp. When it addes the extension schema, it changed the schema name.
WFS is cached connection, which means it will not close connection, so next time when describe the schema, the matching cannot be found anymore, causing the defect.

To fix this problem, make a copy of the original one and added as extension schema, no change the original one.

[ChristineBao]

Attach patch for fixing this ticket. ​http://trac.osgeo.org/mapguide/attachment/ticket/1917/Fix1917.patch

It fixed the above problem, meantime it removes the unnecessary setSchema/setFeatureClass code.

[ChristineBao]

Submit to 2.4j branch in r6441. Not submit to trunk so far.