ERP5TypeLiveTestCase: fix runing only one class from a module

This only apply for running live tests of a test component that defines
multiple classes

You can use for example,
testStandardConfigurationWorkflow.TestStandardConfiguratorWorkflow in
"Tests" field of "Live Tests" dialog to run only
TestStandardConfiguratorWorkflow test class

(cherry picked from commit ced90df1)

product/ERP5Type/tests/ERP5TypeLiveTestCase.py

@@ -179,7 +179,7 @@ class ERP5TypeLiveTestLoader(ERP5TypeTestLoader):
             import erp5.component.test
 
             try:
-                __import__('erp5.component.test.' + name,
+                __import__('erp5.component.test.' + name.split('.')[0],
                            fromlist=['erp5.component.test'],
                            level=0)
             except ImportError: