fix branch in build script

  commit_file="$MERGE_TARGET_COMMIT_FILE"

  ;;

merge-source)

  branch_to_check_out="$FLOAT_REF_BRANCH_MERGE_SOURCE"

  branch_to_check_out="$CI_MERGE_REQUEST_SOURCE_BRANCH_NAME"

  ivas_cod_filename="./$DUT_ENCODER_PATH_FOR_BUILD_DO_NOT_MODIFY"

  ivas_dec_filename="./$DUT_DECODER_PATH_FOR_BUILD_DO_NOT_MODIFY"

  ivas_rend_filename="./$DUT_RENDERER_PATH_FOR_BUILD_DO_NOT_MODIFY"

  ;;

esac

echo "Building $mode binaries"

echo "Building $mode binaries from branch $branch_to_check_out"

# TODO: could probably always be run

if [[ "$mode" == "float-ref" ]]; then