Extract greping-the-log -based tor_bootstrap_progress to our shell library.

... so that it is used in the Iceweasel wrapper script.

config/chroot_local-includes/etc/NetworkManager/dispatcher.d/20-time.sh

@@ -173,11 +173,6 @@ tor_cert_valid_after() {
 	    ${TOR_LOG} | tail -n 1
 }
 
-tor_bootstrap_progress() {
-	grep -o "\[notice\] Bootstrapped [[:digit:]]\+%:" ${TOR_LOG} | \
-	    tail -n1 | sed "s|\[notice\] Bootstrapped \([[:digit:]]\+\)%:|\1|"
-}
-
 tor_cert_lifetime_invalid() {
 	# To be sure that we only grep relevant information, we
 	# should delete the log when Tor is started, which we do

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

@@ -29,6 +29,11 @@ tor_control_setconf() {
 	tor_control_send "SETCONF ${1}" >/dev/null
 }
 
+tor_bootstrap_progress() {
+	grep -o "\[notice\] Bootstrapped [[:digit:]]\+%:" ${TOR_LOG} | \
+	    tail -n1 | sed "s|\[notice\] Bootstrapped \([[:digit:]]\+\)%:|\1|"
+}
+
 # Potential Tor bug: it seems like using this version makes Tor get
 # stuck at "Bootstrapped 5%" quite often. Is Tor sensitive to opening
 # control ports and/or issuing "getinfo status/bootstrap-phase" during