FEM: Use format to avoid error is the message is not pure string

Traceback (most recent call last):
  File "/home/przemo/software/FreeCAD/build/Mod/Fem/TestFem.py", line
229, in test_new_analysis
    ret = self.compare_stats(fea, static_expected_values)
  File "/home/przemo/software/FreeCAD/build/Mod/Fem/TestFem.py", line
147, in compare_stats
    fcc_print(sf_content)
  File "/home/przemo/software/FreeCAD/build/Mod/Fem/TestFem.py", line
55, in fcc_print
    FreeCAD.Console.PrintMessage(message + '\n')
TypeError: can only concatenate list (not "str") to list

Signed-off-by: Przemo Firszt <[email protected]>

src/Mod/Fem/TestFem.py

@@ -52,7 +52,7 @@ mesh_volumes_file = test_file_dir + '/mesh_volumes.csv'
 
 
 def fcc_print(message):
-    FreeCAD.Console.PrintMessage(message + '\n')
+    FreeCAD.Console.PrintMessage('{} \n'.format(message))
 
 
 class FemTest(unittest.TestCase):