[gimp] configure, desktop: fix desktop-file-validate test.

[Jehan Pagès <jehanp src gnome org>]

commit 7a27d81eba11a8069cc5829722ce8f4483449d51
Author: Jehan <jehan girinstud io>
Date:   Sun May 20 18:10:00 2018 +0200

    configure, desktop: fix desktop-file-validate test.
    
    Double copy-paste error! Must have been sleep-coding.

 configure.ac        |    2 +-
 desktop/Makefile.am |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 30a591b..99ff7e5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2290,7 +2290,7 @@ fi
 #################################
 
 AC_PATH_PROG(DESKTOP_FILE_VALIDATE, desktop-file-validate, no)
-if test "x$APPSTREAM_UTIL" != "xno"; then
+if test "x$DESKTOP_FILE_VALIDATE" != "xno"; then
   have_desktop_file_validate="yes"
 else
   have_desktop_file_validate="no (desktop-file-validate not found)"
diff --git a/desktop/Makefile.am b/desktop/Makefile.am
index 306d52c..519dda0 100644
--- a/desktop/Makefile.am
+++ b/desktop/Makefile.am
@@ -81,6 +81,6 @@ if HAVE_APPSTREAM_UTIL
 TESTS += test-appdata.sh
 endif
 
-if HAVE_APPSTREAM_UTIL
+if HAVE_DESKTOP_FILE_VALIDATE
 TESTS += test-desktop.sh
 endif