docker: add expected log functions to alpine docker-start

Some basic functions are required by frrcommon.sh

Signed-off-by: Quentin Young <qlyoung@nvidia.com>

docker/alpine/docker-start

@@ -1,4 +1,18 @@
 #!/bin/ash
 
+if [ -r "/lib/lsb/init-functions" ]; then
+        . /lib/lsb/init-functions
+else
+        log_success_msg() {
+                echo "$@"
+        }
+        log_warning_msg() {
+                echo "$@" >&2
+        }
+        log_failure_msg() {
+                echo "$@" >&2
+        }
+fi
+
 source /usr/lib/frr/frrcommon.sh
 /usr/lib/frr/watchfrr $(daemon_list)