Fix 'install: can't stat' message, when no hook is installed (#310)

aports/main/postmarketos-mkinitfs/APKBUILD

 pkgname=postmarketos-mkinitfs
-pkgver=0.3.0
+pkgver=0.3.1
 pkgrel=1
 pkgdesc="Tool to generate initramfs images for postmarketOS"
 url="https://github.com/postmarketOS"
@@ -27,4 +27,4 @@ package() {
 }
 sha512sums="95e49eb5e7891d319543165290fb7279733e696db8c768d864d87ef36a20b04e1c4e8a1702a2927e7492ea2e9f3d4fdd83d9ea55811969689b9c2483fb3b44c4  init.sh.in
 66207a12dba2be8868d080e69e54dce43c8a3edbbd08a6585f8ad49034e32bbe9184c4c77b5fe49049d7475f930781f48919a12eb4d82c9e0008f6fa6da0d035  init_functions.sh
-9bf70dda59c4c64bef829dcdaf0973168601e91b5478b5d827dbb967c9682b0eedd2a84211fb679e95d5b5e1a12d01ec5baef9b3b12995e376322fd81303c716  mkinitfs.sh"
+81ae1b6c1a96fbefe842b5e2cc8790c4c9761d9c714a8a6d6a623834e290e5255f5695740d38dc5bc2571aa0eeab54bb5ce69fe1457db5ef84b56d8a8e8eee9d  mkinitfs.sh"

aports/main/postmarketos-mkinitfs/mkinitfs.sh

@@ -130,6 +130,7 @@ get_binaries_extra()
 copy_files()
 {
 	for file in $1; do
+		[ -e "$file" ] || continue
 		install -Dm755 "$file" "$2$file"
 	done
 }