fix: Reduce verbosity if version file is missing

As we don't check for the existance of the version file this would
otherwise emit a useless error to the commandline:

    > ==> Building protobuf for [extra-staging] (x86_64)
    > cat: /var/lib/archbuild/extra-staging-x86_64/root/.arch-chroot: No such file or directory
    > ==> Creating chroot for [extra-staging] (x86_64)...

Fix this by just silencing the error, as the check later also covers the
case for empty `CURRENT_CHROOT_VERSION`.

Fixes #272

Component: archbuild
Signed-off-by: Christian Heusel <christian@heusel.eu>

src/arch-nspawn.in

@@ -61,20 +61,13 @@ nspawn_args=(
 	--directory="$working_dir"
 	--setenv="PATH=/usr/local/sbin:/usr/local/bin:/usr/bin"
 	--register=no
+	--slice="devtools-$(systemd-escape "${SUDO_USER:-$USER}")"
+	--machine="arch-nspawn-$$"
 	--as-pid2
 	--console=autopipe
 	--timezone=off
 )
 
-if [[ ${DEVTOOLS_KEEP_UNIT:-0} == 1 ]]; then
-	nspawn_args+=(--keep-unit)
-else
-	nspawn_args+=(
-		--slice="devtools-$(systemd-escape "${SUDO_USER:-$USER}")"
-		--machine="arch-nspawn-$$"
-	)
-fi
-
 if (( ${#cache_dirs[@]} == 0 )); then
 	mapfile -t cache_dirs < <(pacman-conf --config "${pac_conf:-$working_dir/etc/pacman.conf}" CacheDir)
 fi

src/archbuild.in

@@ -80,7 +80,7 @@ check_root SOURCE_DATE_EPOCH,SRCDEST,SRCPKGDEST,PKGDEST,LOGDEST,MAKEFLAGS,PACKAG
 makechrootpkg_args+=("${@:$OPTIND}")
 
 # Automatically recreate the root chroot if a version mismatch is detected
-CURRENT_CHROOT_VERSION=$(cat "${chroots}/${repo}-${arch}/root/.arch-chroot")
+CURRENT_CHROOT_VERSION=$(cat "${chroots}/${repo}-${arch}/root/.arch-chroot" 2>/dev/null)
 if [[ -f "${chroots}/${repo}-${arch}/root/.arch-chroot" ]] && [[ "$CURRENT_CHROOT_VERSION" != "$CHROOT_VERSION" ]]; then
 	warning "Recreating chroot '%s' (%s) as it is not at version %s" "${chroots}/${repo}-${arch}/root" "$CURRENT_CHROOT_VERSION" "$CHROOT_VERSION"
 	clean_first=true