snap: Fix compile warning

1 job for master in 2 minutes and 22 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
failed #212981
build-gnome-software

00:02:22

 
Name Stage Failure
failed
build-gnome-software Build

Complete!
$ dnf install -y https://people.freedesktop.org/~hughsient/temp/libappstream-glib-0.7.14-0.641.20181015git.fc29.x86_64.rpm https://people.freedesktop.org/~hughsient/temp/libappstream-glib-devel-0.7.14-0.641.20181015git.fc29.x86_64.rpm
Last metadata expiration check: 0:01:13 ago on Tue Feb 12 03:21:20 2019.
libappstream-glib-0.7.14-0.641.20181015git.fc29 211 kB/s | 302 kB 00:01
[MIRROR] libappstream-glib-devel-0.7.14-0.641.20181015git.fc29.x86_64.rpm: Curl error (28): Timeout was reached for https://people.freedesktop.org/~hughsient/temp/libappstream-glib-devel-0.7.14-0.641.20181015git.fc29.x86_64.rpm [Connection timed out after 30002 milliseconds]
[FAILED] libappstream-glib-devel-0.7.14-0.641.20181015git.fc29.x86_64.rpm: Curl error (28): Timeout was reached for https://people.freedesktop.org/~hughsient/temp/libappstream-glib-devel-0.7.14-0.641.20181015git.fc29.x86_64.rpm [Connection timed out after 30002 milliseconds]
Curl error (28): Timeout was reached for https://people.freedesktop.org/~hughsient/temp/libappstream-glib-devel-0.7.14-0.641.20181015git.fc29.x86_64.rpm [Connection timed out after 30002 milliseconds]
ERROR: Job failed: exit code 1