SwDBManager: fix relative reference of embedded data source

When the MM wizard creates an embedded data source definition, then we
used to always write absolute references to e.g. the data source Calc
file. Pass BaseURI to the filter, so in case the document and the data
source is in the same directory, relative references can be written.

Change-Id: Iaa316adaf435f82bb574c7e5085ac04bf13a71f8

sw/source/uibase/dbui/dbmgr.cxx

@@ -2635,7 +2635,8 @@ OUString SwDBManager::LoadAndRegisterDataSource(const DBConnURITypes type, const
                 aSequence = comphelper::InitPropertySequence(
                 {
                     {"TargetStorage", uno::makeAny(xStorage)},
-                    {"StreamRelPath", uno::makeAny(aStreamRelPath)}
+                    {"StreamRelPath", uno::makeAny(aStreamRelPath)},
+                    {"BaseURI", uno::makeAny(aOwnURL)}
                 });
 
                 // Refer to the sub-storage name in the document settings, so