[gnome-software/gnome-3-26] Release version 3.26.4

[Kalev Lember <klember src gnome org>]

commit 2d0d2d7bc464a35a9d26f6a6485bf38c716ace86
Author: Kalev Lember <klember redhat com>
Date:   Sun Dec 17 09:57:50 2017 +0100

    Release version 3.26.4

 NEWS                                           |   16 ++++++++++++++++
 data/appdata/org.gnome.Software.appdata.xml.in |   18 ++++++++++++++++++
 2 files changed, 34 insertions(+), 0 deletions(-)
---
diff --git a/NEWS b/NEWS
index 4641d4c..8b27fdc 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,19 @@
+Version 3.26.4
+~~~~~~~~~~~~~~
+Released: 2017-12-17
+
+This is a stable release with the following changes:
+ * Fix crashes in the repos plugin due to missing locking
+ * Work around Firefox deleting rpm/deb files downloaded to /tmp when closing
+ * Do not require the user to keep clicking 'More reviews' after each click
+ * Fix a critical when updating (flatpak) packages live
+ * fwupd: Prepend the vendor name to the device name if not included
+ * Improve SPDX ID parsing when working out if it is 'free'
+ * packagekit: Do not crash when getting an invalid ID from PackageKit
+ * Do not crash when closing the source dialog while it is loading
+
+This release also updates translations.
+
 Version 3.26.3
 ~~~~~~~~~~~~~~
 Released: 2017-11-21
diff --git a/data/appdata/org.gnome.Software.appdata.xml.in b/data/appdata/org.gnome.Software.appdata.xml.in
index 0704c37..26076ee 100644
--- a/data/appdata/org.gnome.Software.appdata.xml.in
+++ b/data/appdata/org.gnome.Software.appdata.xml.in
@@ -46,6 +46,24 @@
    Validate with `appstream-util validate *.appdata.xml`
   -->
   <releases>
+    <release date="2017-12-17" version="3.26.4">
+      <description>
+        <p>
+          This is a stable release with the following changes:
+        </p>
+        <ul>
+          <li>Fix crashes in the repos plugin due to missing locking</li>
+          <li>Work around Firefox deleting rpm/deb files downloaded to /tmp when closing</li>
+          <li>Do not require the user to keep clicking 'More reviews' after each click</li>
+          <li>Fix a critical when updating (flatpak) packages live</li>
+          <li>fwupd: Prepend the vendor name to the device name if not included</li>
+          <li>Improve SPDX ID parsing when working out if it is 'free'</li>
+          <li>packagekit: Do not crash when getting an invalid ID from PackageKit</li>
+          <li>Do not crash when closing the source dialog while it is loading</li>
+        </ul>
+        <p>This release also updates translations.</p>
+      </description>
+    </release>
     <release date="2017-11-21" version="3.26.3">
       <description>
         <p>