Eliminate implicit relative imports

Convert to either absolute imports or explicit relative imports

plinth/actions.py

@@ -78,8 +78,8 @@ import os
 import pipes
 import subprocess
 
-import cfg
-from errors import ActionError
+from plinth import cfg
+from plinth.errors import ActionError
 
 
 LOGGER = logging.getLogger(__name__)

plinth/context_processors.py

@@ -20,7 +20,8 @@ Django context processors to provide common data to templates.
 """
 
 import re
-import cfg
+
+from plinth import cfg
 
 
 def common(request):

plinth/modules/system/__init__.py

@@ -20,7 +20,7 @@ Plinth module for system section page
 """
 
 from . import system
-from system import init
+from .system import init
 
 
 __all__ = ['system', 'init']