gen_merge_report.sh: Move message referring to $merge_files after it's set

Otherwise the empty value was always output in it.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I8c9718eddb4a2acb76fc5717fa2dd3e4f499cdbd
diff --git a/script/gen_merge_report.sh b/script/gen_merge_report.sh
index 2d8e40b..2fbc6a8 100644
--- a/script/gen_merge_report.sh
+++ b/script/gen_merge_report.sh
@@ -132,11 +132,11 @@
             exit 0;;
 esac
 export MERGE_JSON="$OUTDIR/merge.json"
-echo "Merging $merge_files coverage files..."
 source "$CI_ROOT/script/test_definitions.sh"
 mkdir -p $OUTDIR
 pushd $OUTDIR
     merge_files=$(create_merge_cfg)
+    echo "Merging $merge_files coverage files..."
     # Only merge when more than 1 test result
     if [ "$merge_files" -lt 2 ] ; then
         exit 0