sleep for 0.1s instead of 1s in the wait_for_status loop

This reduces `weave launch|launch-dns` execution time.

Closes #992.

weave

@@ -183,6 +183,18 @@ command_exists() {
     command -v $1 >/dev/null 2>&1
 }
 
+fractional_sleep() {
+    if [ -z "$HAS_FRACTIONAL_SLEEP" ] ; then
+        HAS_FRACTIONAL_SLEEP=1
+        sleep 0.01 >/dev/null 2>&1 || HAS_FRACTIONAL_SLEEP=0
+    fi
+    if [ $HAS_FRACTIONAL_SLEEP -eq 1 ] ; then
+        sleep $1
+    else
+        sleep $((${1%.*} + 1))
+    fi
+}
+
 run_iptables() {
     # -w is recent addition to iptables
     if [ -z "$CHECKED_IPTABLES_W" ] ; then
@@ -585,7 +597,7 @@ wait_for_status() {
             echo "$err_msg" >&2
             return 1
         fi
-        sleep 1
+        fractional_sleep 0.1
     done
 }