[docker-syncd-brcm]: Sleep to allow syncd to create socket before calling bcmcmd (#733)

* [docker-syncd-brcm]: Sleep to allow syncd to create socket before calling bcmcmd

* Instead of fixed sleep interval, continually check for presence of socket

platform/broadcom/docker-syncd-brcm/start.sh

@@ -10,6 +10,14 @@ supervisorctl start syncd
 
 # If this platform has an initialization file for the Broadcom LED microprocessor, load it
 if [ -r ${PLATFORM_DIR}/led_proc_init.soc ]; then
+    # Wait until syncd has created the socket for bcmcmd to connect to
+    while true; do
+        if [ -e /var/run/sswsyncd/sswsyncd.socket ]; then
+            break
+        fi
+        sleep 1
+    done
+
     /usr/bin/bcmcmd -t 60 "rcload ${PLATFORM_DIR}/led_proc_init.soc"
 fi