On Windows, avoid using rsync for file-to-file copies, since rsync is not always available there.

Installing git-annex with stack rsync won't be available.
Also, using the git-annex installer with 64 bit git installs a non-working
rsync binary because it's linked with libraries provided by 32 bit git.

CHANGELOG

@@ -31,6 +31,8 @@ git-annex (7.20190130) UNRELEASED; urgency=medium
     filesystem, that left the repository in indirect mode.
   * Fix path separator bug on Windows that completely broke git-annex
     since version 7.20190122.
+  * On Windows, avoid using rsync for file-to-file copies, since rsync is not
+    always available there.
 
  -- Joey Hess <id@joeyh.name>  Wed, 30 Jan 2019 12:30:22 -0400
 

Remote/Git.hs

@@ -709,7 +709,9 @@ onLocalFast repo r a = onLocal repo r $ Annex.BranchState.disableUpdate >> a
 rsyncOrCopyFile :: [CommandParam] -> FilePath -> FilePath -> MeterUpdate -> Annex Bool
 rsyncOrCopyFile rsyncparams src dest p =
 #ifdef mingw32_HOST_OS
-	dorsync
+	-- rsync is only available on Windows in some inatallation methods,
+	-- and is not strictly needed here, so don't use it.
+	docopy
   where
 #else
 	ifM (sameDeviceIds src dest) (docopy, dorsync)