test: Make log errors easier to find

We were using greenprint for failures, which makes it hard to quickly
find where the tests failed. This switches errors to use redprint, and
adds it to places that were simply using echo before doing an exit 1.

test/cases/ostree.sh

@@ -146,7 +146,7 @@ case "${ID}-${VERSION_ID}" in
         SYSROOT_RO="true"
         ;;
     *)
-        echo "unsupported distro: ${ID}-${VERSION_ID}"
+        redprint "unsupported distro: ${ID}-${VERSION_ID}"
         exit 1;;
 esac
 
@@ -308,7 +308,7 @@ build_image() {
 
     # Did the compose finish with success?
     if [[ $COMPOSE_STATUS != FINISHED ]]; then
-        echo "Something went wrong with the compose. 😢"
+        redprint "Something went wrong with the compose. 😢"
         exit 1
     fi
 }
@@ -350,7 +350,7 @@ check_result () {
     if [[ $RESULTS == 1 ]]; then
         greenprint "💚 Success"
     else
-        greenprint "❌ Failed"
+        redprint "❌ Failed"
         clean_up
         exit 1
     fi