[geary/geary-0.12] Update flatpak-builder for stable branch.

[Michael Gratton <mjog src gnome org>]

commit 175134fdb3d6c8c844e27d9076c17de958cdc8bb
Author: Michael James Gratton <mike vee net>
Date:   Mon Oct 2 21:48:00 2017 +1100

    Update flatpak-builder for stable branch.

 org.gnome.Geary.json |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/org.gnome.Geary.json b/org.gnome.Geary.json
index 2f809b7..fa9ece7 100644
--- a/org.gnome.Geary.json
+++ b/org.gnome.Geary.json
@@ -2,11 +2,10 @@
 {
     "app-id": "org.gnome.Geary",
     "runtime": "org.gnome.Platform",
-    "runtime-version": "master",
+    "runtime-version": "3.26",
     "sdk": "org.gnome.Sdk",
     "command": "geary",
-    "tags": ["nightly"],
-    "desktop-file-name-prefix": "(Nightly) ",
+    "tags": [],
     "rename-icon": "geary",
     "copy-icon": true,
     "finish-args": [