remove container config during finalize

Since the container config for the build is created with O_EXCL, multiple
consecutive invocations of `make default` fail, if the config file exists.

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>

PVE/AAB.pm

@@ -675,6 +675,8 @@ sub clean {
     unlink $self->{'pacman.conf'};
     $self->ve_destroy();
     unlink '.veid';
+    unlink $self->{veconffile};
+
     rmtree $self->{pkgcache} if $all;
 }