Fix for analysis datasource import

When importing individual schema files, the catalog name was being derived from the name of the file rather than the value of the name attribute in the schema node of the source file.  The result was that importing the steelwheels.mondrian.xml file produced a catalog name of "steelwheels" in JCR but displayed as "SteelWheels" in the interface.  Because of this naming mismatch it appeared the same data source was getting stored twice.  What was really happening is the schema was stored under a different name and would never be accessible.

This changes uses the contents of the imported file to derive the catalog name.  This is the same net behavior performed by the bulk zip file import logic.