smbprovider: Add SMB1 unsupported ErrorType

Adds an error to the smbprovider::ErrorType enum to be used to
differentiate between a generic failure and a failure because a
specified share is SMB1 which we do not support.

BUG=chromium:757625
TEST=emerges
Change-Id: Ia2847f903d471c4015681a04303d2f01ce4310f1
Reviewed-on: https://chromium-review.googlesource.com/1195586
Commit-Ready: Zentaro Kavanagh <zentaro@chromium.org>
Tested-by: Zentaro Kavanagh <zentaro@chromium.org>
Tested-by: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
diff --git a/dbus/smbprovider/directory_entry.proto b/dbus/smbprovider/directory_entry.proto
index 8b77cdc..feeccc4 100644
--- a/dbus/smbprovider/directory_entry.proto
+++ b/dbus/smbprovider/directory_entry.proto
@@ -38,6 +38,7 @@
   ERROR_DBUS_PARSE_FAILED = 50;
   ERROR_COPY_PENDING = 51;
   ERROR_COPY_FAILED = 52;
+  ERROR_SMB1_UNSUPPORTED = 53;
 }
 
 message DirectoryEntryProto {