Change user agent string for docker refresh

salt/common/tools/sbin/so-docker-refresh

@@ -45,4 +45,5 @@ version_check
 HOSTNAME=$(hostname)
 # List all the containers
 container_list
+CURLTYPE=refresh
 update_docker_containers

salt/common/tools/sbin/so-image-common

@@ -87,6 +87,14 @@ container_list() {
     fi
 }
 
+operating_system() {
+  if [ -f /etc/redhat-release ]; then
+    OS=CentOS
+  else
+    OS=Ubuntu
+  fi
+}
+
 update_docker_containers() {
   # Let's make sure we have the public key
   curl -sSL https://raw.githubusercontent.com/Security-Onion-Solutions/securityonion/master/KEYS | gpg --import -
@@ -106,7 +114,7 @@ update_docker_containers() {
     docker pull $CONTAINER_REGISTRY/$IMAGEREPO/$i:$VERSION
     
     # Get signature
-    curl https://sigs.securityonion.net/$VERSION/$i:$VERSION.sig --output $SIGNPATH/$i:$VERSION.sig
+    curl -A "$OS $CURLTYPE" https://sigs.securityonion.net/$VERSION/$i:$VERSION.sig --output $SIGNPATH/$i:$VERSION.sig
     if [[ $? -ne 0 ]]; then
       echo "Unable to pull signature file for $i:$VERSION"
       exit 1