Merge pull request #1302 from cam72cam/1298_fix_auth_mast_session_info

Fix Auth.MAST session info retrieval

Author: bsipocz

astroquery/mast/core.py

@@ -705,6 +705,7 @@ def _session_info(self, silent=False):  # pragma: no cover
         """
 
         # get user information
+        self._session.headers["Accept"] = "application/json"
         response = self._session.request("GET", self._SESSION_INFO_URL)
 
         infoDict = json.loads(response.text)