Fix non-signed builds

FS#48382

archiso/mkarchiso

@@ -328,7 +328,9 @@ command_prepare () {
         _mkairootfs_img
     fi
     _mkchecksum
-    [[ ${gpg_key} ]] && _mksignature
+    if [[ ${gpg_key} ]]; then
+      _mksignature
+    fi
 }
 
 # Install packages on airootfs.

configs/releng/build.sh

@@ -8,6 +8,7 @@ iso_version=$(date +%Y.%m.%d)
 install_dir=arch
 work_dir=work
 out_dir=out
+gpg_key=
 
 arch=$(uname -m)
 verbose=""