Makes quickstart more REPL friendly [(#2354)](GoogleCloudPlatform/python-docs-samples#2354)

Author: gguuss

samples/snippets/quickstart/quickstart.py

@@ -32,9 +32,7 @@ def run_quickstart():
     # [END vision_python_migration_client]
 
     # The name of the image file to annotate
-    file_name = os.path.join(
-        os.path.dirname(__file__),
-        'resources/wakeupcat.jpg')
+    file_name = os.path.abspath('resources/wakeupcat.jpg')
 
     # Loads the image into memory
     with io.open(file_name, 'rb') as image_file: