Make shellcheck happy about the max31785-msl script

Signed-off-by: Anton D. Kachalov <gmouse@google.com>
Change-Id: I84a6ce4fa6ff9172c2c91f93e6d01784d9ea46f9
diff --git a/msl/max31785-msl b/msl/max31785-msl
index b3673e6..6b47395 100644
--- a/msl/max31785-msl
+++ b/msl/max31785-msl
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # Copyright © 2017 IBM Corporation
 #
@@ -22,7 +22,7 @@
 
 main()
 {
-    usage="Usage: $(basename $0) -p PATH... -b BUS_NUMBER -r REVISION"
+    usage="Usage: $(basename "$0") -p PATH... -b BUS_NUMBER -r REVISION"
     while getopts p:b:r:h key; do
         case $key in
             p)
@@ -39,7 +39,7 @@
                 exit
                 ;;
             \?)
-                echo -e \\n"Unrecognized option"
+                printf "\nUnrecognized option\n"
                 echo "$usage" >&2
                 exit 1
                 ;;
@@ -57,18 +57,18 @@
     local dbus
 
     dbus=$(mapper get-service /xyz/openbmc_project/inventory)
-    actual=$(i2cget -f -y $bus 0x52 0x9b w)
+    actual=$(i2cget -f -y "$bus" 0x52 0x9b w)
 
     if (( actual >= revision )); then
         state="true"
     fi
 
     for path in $paths; do
-        busctl call $dbus /xyz/openbmc_project/inventory \
+        busctl call "$dbus" /xyz/openbmc_project/inventory \
             xyz.openbmc_project.Inventory.Manager Notify 'a{oa{sa{sv}}}' 1 \
-            $path 1 \
+            "$path" 1 \
             xyz.openbmc_project.Inventory.Decorator.MeetsMinimumShipLevel \
-            1 MeetsMinimumShipLevel b $state
+            1 MeetsMinimumShipLevel b "$state"
     done
 }