Use full path for dconf in posttrans script

We don't have PATH correctly set up to contain /app/bin when installing
packages for flatpak containers. This led to the 'dconf update'
posttrans script to fail to execute when building dconf-editor flatpak.

As a workaround, just use the full path here.

https://bugzilla.redhat.com/show_bug.cgi?id=1950829

dconf.spec

@@ -2,7 +2,7 @@
 
 Name:           dconf
 Version:        0.40.0
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        A configuration system
 
 License:        LGPLv2+ and GPLv2+ and GPLv3+
@@ -59,7 +59,7 @@ mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/dconf/db/site.d/locks
 mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/dconf/db/distro.d/locks
 
 %posttrans
-dconf update
+%{_bindir}/dconf update
 
 %post
 %systemd_user_post dconf.service
@@ -103,6 +103,9 @@ dconf update
 %{_datadir}/vala
 
 %changelog
+* Mon Apr 19 2021 Kalev Lember <klember@redhat.com> - 0.40.0-3
+- Use full path for dconf in posttrans script (#1950829)
+
 * Wed Mar 31 2021 Kalev Lember <klember@redhat.com> - 0.40.0-2
 - Avoid hardcoding man page compression