Fetch Mantis projects and filters on test connection (workaround for support 38685)

It seems that requesting access levels may cause server side
errors in some rare configuration (PHP 5.4 with nusoap library). Before
problem is reproduced exactly I rollback to previously used approach
when projects and filters are refereshed instead for "Login/Test"
functionality.

plugins/tasks/tasks-core/src/com/intellij/tasks/mantis/MantisRepository.java

@@ -153,7 +153,7 @@ public class MantisRepository extends BaseRepositoryImpl {
       protected void doTest() throws Exception {
         myProjects = null;
         try {
-          createSoap().mc_enum_access_levels(getUsername(), getPassword());
+          refreshProjects();
         }
         catch (Exception e) {
           throw handleException(e);