add /bin to exec path

manifests/chroot.pp

@@ -61,7 +61,7 @@ define su_debuild::chroot(
 
     # 0. Create the chroot WITHOUT the stanford-keyring.
     exec { "cowbuilder --create ${name}":
-      path    => '/usr/sbin:/usr/bin',
+      path    => '/usr/sbin:/usr/bin:/bin',
       command => "cowbuilder --create --basepath ${path} ${options}",
       creates => $path,
       require => [ Package['cowdancer'],