[MONDRIAN-1844] Reverts the conversion of XmlaServlet to IOlapService. Should have been reverted when I backed out my merge. Also fixes a small issue in MondrianCatalogRepositoryHelper where the properties were pulle dout by calling toString instead of getString.
Merge branch 'master' of https://github.com/pentaho/pentaho-platform
Merge pull request #1185 from lucboudreau/master

[MONDRIAN-1844] Reverts a merge to PentahoXmlaServlet which was omitted in a previous unmerge.