Refactor some logic in init_dirs

Eliminates the one remaining warning in there and simplifies the logic a
bit.

The overall procedure seems to work like this:
 1. Check if Oblivion.ini exists in Oblivion's directory.
 2. If the file exists, check if bUseMyGamesDirectory exists and retrieve its value.
 3. If Oblivion.ini exists and the bUseMyGamesDirectory option is present and it's set to 0, set the saveBase and mods dirs relative to the Oblivion directory.
 4. If any of the above are false, keep the saveBase and mods dirs at their default values.

This also seems to be Oblivion-specific - STEP calls
bUseMyGamesDirectory 'unused' for Skyrim, but I'd have to ask e.g.
Nukem for further information on this.

Mopy/bash/initialization.py

@@ -151,23 +151,19 @@ def init_dirs(bashIni_, personal, localAppData, game_info):
     # actually matter.
     # Utumno: not sure how/if this applies to other games
     data_oblivion_ini = dirs['app'].join(game_info.iniFiles[0])
-    use_data_dir = False
+    game_ini_path = dirs['saveBase'].join(game_info.iniFiles[0])
+    dirs['mods'] = dirs['app'].join(u'Data')
     if data_oblivion_ini.exists():
         oblivionIni = ConfigParser()
         oblivionIni.read(data_oblivion_ini.s)
         # is bUseMyGamesDirectory set to 0?
-        use_data_dir = get_ini_option(oblivionIni,
-                                      u'bUseMyGamesDirectory') == u'0'
-    if use_data_dir:
-        game_ini_path = data_oblivion_ini
-        # Set the save game folder to the Oblivion directory
-        dirs['saveBase'] = dirs['app']
-        # Set the data folder to sLocalMasterPath
-        dirs['mods'] = dirs['app'].join(get_ini_option(oblivionIni,
-            u'SLocalMasterPath') or u'Data')
-    else:
-        game_ini_path = dirs['saveBase'].join(game_info.iniFiles[0])
-        dirs['mods'] = dirs['app'].join(u'Data')
+        if get_ini_option(oblivionIni, u'bUseMyGamesDirectory') == u'0':
+            game_ini_path = data_oblivion_ini
+            # Set the save game folder to the Oblivion directory
+            dirs['saveBase'] = dirs['app']
+            # Set the data folder to sLocalMasterPath
+            dirs['mods'] = dirs['app'].join(get_ini_option(oblivionIni,
+                u'SLocalMasterPath') or u'Data')
     # these are relative to the mods path so they must be set here
     dirs['patches'] = dirs['mods'].join(u'Bash Patches')
     dirs['tweaks'] = dirs['mods'].join(u'INI Tweaks')