Drop an optimization in chroot_archives that has undesired side-effects

Thanks to jnqnfe for the patch.

Closes: #775989

debian/changelog

@@ -31,6 +31,8 @@ live-build (1:20160105) UNRELEASED; urgency=medium
   * Manual pages updates by jnqnfe. Closes: #774730
   * Drop left-over translation files for removed lb_testroot command.
   * Get rid of useless bootstrap_archive-keys script. Closes: #773775
+  * Drop an optimization in chroot_archives that has undesired side-effects.
+    Thanks to jnqnfe for the patch. Closes: #775989 
 
   [ Kristian Klausen ]
   * Include ext{3,4} journal size when calculating image size. Closes: #801712

scripts/build/chroot_archives

@@ -456,17 +456,6 @@ then
 fi
 
 		# Configure generic indices
-		# Don't do anything if it's not required
-		if [ "${LB_PARENT_MIRROR_CHROOT}" = "${LB_PARENT_MIRROR_BINARY}" ] && \
-		[ "${LB_PARENT_MIRROR_CHROOT_SECURITY}" = "${LB_PARENT_MIRROR_BINARY_SECURITY}" ] && \
-		[ ! -d chroot/root/packages ]
-		then
-			# Removing stage file
-			rm -f .build/chroot_archives
-
-			exit 0
-		fi
-
 		# Cleaning apt list cache
 		rm -rf chroot/var/lib/apt/lists
 		mkdir -p chroot/var/lib/apt/lists/partial