[python] Use assertEqual instead of deprecated assertEquals-

Prevents warnings like
```
1: test_faults (tests.test_state.TestState2.test_faults) ... /<<PKGBUILDDIR>>/obj-arm-linux-gnueabihf/python/tests/test_state.py:124: DeprecationWarning: Please use assertEqual instead.
1:   self.assertEquals([], self.state.faultNames())
```
On Debian unstable.

python/tests/test_state.py

@@ -121,7 +121,7 @@ SATNUM
             self.state.tables().evaluate(tab, 0, 'NO', 1)
 
     def test_faults(self):
-        self.assertEquals([], self.state.faultNames())
+        self.assertEqual([], self.state.faultNames())
         parser = Parser()
         faultdeck = parser.parse_string(self.FAULTS_DECK)
         faultstate = EclipseState(faultdeck)