[pitivi] flatpak: Update remote-add usage

[Alexandru Băluț <alexbalut src gnome org>]

commit 97fb9eee54aae397d8c4d2ab2e945ec2a531d874
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon Oct 31 11:25:30 2016 +0100

    flatpak: Update remote-add usage

 build/flatpak/pitivi-flatpak |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/build/flatpak/pitivi-flatpak b/build/flatpak/pitivi-flatpak
index 6a5fbf0..3c3e0ba 100755
--- a/build/flatpak/pitivi-flatpak
+++ b/build/flatpak/pitivi-flatpak
@@ -227,7 +227,7 @@ class FlatpakRepos(FlatpakObject):
             else:
                 return None
         else:
-            self.flatpak("remote-add", repo.name, "--from=" +
+            self.flatpak("remote-add", repo.name, "--from" +
                          repo.repo_file.name,
                          comment="Adding repo %s" % repo.name)