Update Azure script

- Minor fix

Author: hwdsl2

azure/install.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 
-export VPN_IPSEC_PSK=$1
-export VPN_USER=$2
-export VPN_PASSWORD=$3
+export VPN_IPSEC_PSK="$1"
+export VPN_USER="$2"
+export VPN_PASSWORD="$3"
 
 wget -t 3 -T 30 -nv -O vpn.sh https://raw.githubusercontent.com/hwdsl2/setup-ipsec-vpn/master/vpnsetup.sh && sh vpn.sh