[shotwell] Fix folder sidebar with DAV

[Jens Georg <jensgeorg src gnome org>]

commit 1786a3a69dd79f378ba4f669d2e28fe9c5d10a7b
Author: Jens Georg <mail jensge org>
Date:   Sat Jan 13 21:48:28 2018 +0100

    Fix folder sidebar with DAV
    
    Shotwell tried to go up to the root folder, but if a concrete path is
    mounted, the parent might not have a path associated
    
    So we stop if there is either no parent or the parent does not have a
    local mount representation
    
    https://bugzilla.gnome.org/show_bug.cgi?id=792498

 src/folders/FoldersBranch.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/folders/FoldersBranch.vala b/src/folders/FoldersBranch.vala
index ee0f080..5de7082 100644
--- a/src/folders/FoldersBranch.vala
+++ b/src/folders/FoldersBranch.vala
@@ -76,7 +76,7 @@ public class Folders.Branch : Sidebar.Branch {
         
         // add the path elements in reverse order up to home directory
         File? parent = file.get_parent();
-        while (parent != null) {
+        while (parent != null && parent.get_path() != null) {
             // don't process paths above the user's home directory
             if (parent.equal(home_dir.get_parent()))
                 break;