Be more aggressive when tearing down chroots.

This way the chroot browsers will close faster.

config/chroot_local-includes/usr/local/lib/tails-shell-library/chroot-browser.sh

@@ -15,10 +15,10 @@ try_cleanup_browser_chroot () {
     local chroot="${1}"
     local cow="${2}"
     local user="${3}"
-    try_for 10 "pkill -u ${user} 1>/dev/null 2>&1" || \
+    try_for 10 "pkill -u ${user} 1>/dev/null 2>&1" 0.1 || \
         pkill -9 -u ${user} 1>/dev/null 2>&1
     for mnt in ${chroot}/dev ${chroot}/proc ${chroot} ${cow}; do
-        try_for 10 "umount ${mnt} 2>/dev/null"
+        try_for 10 "umount ${mnt} 2>/dev/null" 0.1
     done
     rmdir ${cow} ${chroot} 2>/dev/null
 }