Story SW-300: fix newline error in stationtest

LCU/Maintenance/MDB_tools/cli/mdb_loader.py

@@ -73,6 +73,8 @@ def is_station_test(content):
     """
     pattern = r'(?:\d{8})(?:\,.*)*'
     for line in content:
+        if line is '':
+            continue
         if not re.match(pattern, line):
             return False
     return True
@@ -125,8 +127,7 @@ def compose_api_url_for_given_test_type(content):
     elif is_rtsm_test(content):
         query = 'rtsm/insert_raw'
     else:
-        raise ValueError('The path format cannot refer both to RTSM and station test. ' +
-                         'Please specify either --station_test or --rtsm')
+        raise ValueError('The file content is not a RTSM nor a station test output.')
     return query