prevent exporttree=yes on remotes that don't support exports

Don't allow "exporttree=yes" to be set when the special remote
does not support exports. That would be confusing since the user would
set up a special remote for exports, but `git annex export` to it would
later fail.

This commit was supported by the NSF-funded DataLad project.

1 files changed, 1 insertions, 0 deletions

diff --git a/Remote.hs b/Remote.hs
index 877c9f37d..8d826712c 100644
--- a/Remote.hs
+++ b/Remote.hs
@@ -53,6 +53,7 @@ module Remote (
 	checkAvailable,
 	isXMPPRemote,
 	claimingUrl,
+	isExportSupported,
 ) where
 
 import Data.Ord