Fix get_debootstrap script

Now it extracts and calls the program properly, if it isn't already
installed.

Also, the script `debian/cleanup_everything` removes debootstrap and
both of the created Debian roots, returning the repository to the same
state it clones in as.

debian/cleanup_everything

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+if test `id -u` -ne 0
+then
+    echo "$0 must be run as root."
+    return
+fi
+
+if test -d test_environment
+then
+    # Call this script that automatically unmounts the mount points too.
+    ./destroy_environment
+fi
+
+if test -d clean_environment
+then
+    echo "Removing clean_environment"
+    rm -r clean_environment
+fi
+
+if test -d debootstrap
+then
+    echo "Removing debootstrap"
+    rm -r debootstrap
+fi
+
+if test -f debootstrap.tar.gz
+then
+    echo "Removing debootstrap.tar.gz"
+    rm debootstrap.tar.gz
+fi
+