export-pkgbuild-keys: fix export for packages without validpgpkeys

In case the validpgpkeys array is empty or undefined, the empty printf
line only included a single line break which lead to mapfile -t
consuming it as an array with 1 element consisting of an empty string.

Fix this by only calling the printf in case the validpgpkeys array is
not empty. Without any output, the mapfile -t will simply produce an
empty array.

Signed-off-by: Levente Polyak <anthraxx@archlinux.org>

0 files changed, 0 insertions, 0 deletions