Remove astroquery/utils/decorators.py

The deleted file was no longer necessary because everything it defined
can be safely imported directly from `astropy`, and there was only a
single instance in the code where that was not being done already.

Author: eerovaher

astroquery/cadc/core.py

@@ -18,7 +18,7 @@
 from ..query import BaseQuery
 from bs4 import BeautifulSoup
 from astropy.utils.exceptions import AstropyDeprecationWarning
-from astroquery.utils.decorators import deprecated
+from astropy.utils.decorators import deprecated
 from astropy import units as u
 from . import conf