When you delete the online linkage and click the save button, the element is removed from the metadata, but the next time ArcGIS synchronizes the metadata. the path is added again.
To avoid this, you could turn off the automatic metadata creation and updating functions, but instead, we recommend leaving the automatic updating active and typing the text 'see distribution information' in the online linkage field. Then, type the distributor details in the Distributor tab.
For more information on creating and updating metadata, see "Using ArcCatalog," p. 135.