errors: use detailed exit code for detected case-collision

Differential Revision: https://phab.mercurial-scm.org/D11828

mercurial/scmutil.py

@@ -341,7 +341,7 b' class casecollisionauditor(object):'
         if fl in self._loweredfiles and f not in self._dirstate:
             msg = _(b'possible case-folding collision for %s') % f
             if self._abort:
-                raise error.Abort(msg)
+                raise error.StateError(msg)
             self._ui.warn(_(b"warning: %s\n") % msg)
         self._loweredfiles.add(fl)
         self._newfiles.add(f)

tests/test-casecollision.t

@@ -12,7 +12,7 b' test file addition with colliding case'
   ? A
   $ hg add --config ui.portablefilenames=abort A
   abort: possible case-folding collision for A
-  [255]
+  [20]
   $ hg st
   A a
   ? A