filelog: drop _generaldelta attribute (API)

With changegroup moving to emitrevisions(), this revlog-specific
attribute is no longer used and can be deleted. Good riddance.

Differential Revision: https://phab.mercurial-scm.org/D4727

mercurial/filelog.py

@@ -25,8 +25,6 b' class filelog(object):'
         # Full name of the user visible file, relative to the repository root.
         # Used by LFS.
         self._revlog.filename = path
-        # Used by changegroup generation.
-        self._generaldelta = self._revlog._generaldelta
 
     def __len__(self):
         return len(self._revlog)

mercurial/repository.py

@@ -741,13 +741,6 b' class ifilemutation(interfaceutil.Interf'
 class ifilestorage(ifileindex, ifiledata, ifilemutation):
     """Complete storage interface for a single tracked file."""
 
-    _generaldelta = interfaceutil.Attribute(
-        """Whether deltas can be against any parent revision.
-
-        TODO this is used by changegroup code and it could probably be
-        folded into another API.
-        """)
-
     def files():
         """Obtain paths that are backing storage for this file.
 

tests/simplestorerepo.py

@@ -106,9 +106,6 b' class filestorage(object):'
         self._index = []
         self._refreshindex()
 
-        # This is used by changegroup code :/
-        self._generaldelta = True
-
     def _refreshindex(self):
         self._indexbynode.clear()
         self._indexbyrev.clear()