Normalize relative path for emulator config file

Previously we couldn't use a relative path in --config option
because it was interpreted as a path relative to the package dir.

Task: 49792
Story: 2011082
Change-Id: I59664991079a969a5af93114a0ab45fd36a4bcbe

sushy_tools/emulator/main.py

@@ -90,7 +90,7 @@ class Application(flask.Flask):
 
     def configure(self, config_file=None, extra_config=None):
         if config_file:
-            self.config.from_pyfile(config_file)
+            self.config.from_pyfile(os.path.abspath(config_file))
         if extra_config:
             self.config.update(extra_config)