[PATCH acme] acme: fix USER_AGENT variable interpolation in curl calls

[Aaron Carson <aaron@aaroncarson.co.uk>]

Signed-off-by: Aaron Carson <aaron@aaroncarson.co.uk>
---
Hi folks, just a small fix - noticed that the user agent being seen by
my DNS server was literally USER_AGENT when updating DNS for ACME. I
know the contribution guide says to discuss before sending in a patch -
but for a two character fix, thought that was unnecessary. Apologies if
not though. Thanks!

 src/proxmox-acme | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/proxmox-acme b/src/proxmox-acme
index 705f7df..39c770b 100644
--- a/src/proxmox-acme
+++ b/src/proxmox-acme
@@ -348,9 +348,9 @@ _get_impl() {
     _CURL="$_CURL --connect-timeout $t"
   fi
   if [ "$onlyheader" ]; then
-    $_CURL -I --user-agent "USER_AGENT" -H "$_H1" -H "$_H2" -H "$_H3" -H "$_H4" -H "$_H5" "$url"
+    $_CURL -I --user-agent "$USER_AGENT" -H "$_H1" -H "$_H2" -H "$_H3" -H "$_H4" -H "$_H5" "$url"
   else
-    $_CURL --user-agent "USER_AGENT" -H "$_H1" -H "$_H2" -H "$_H3" -H "$_H4" -H "$_H5" "$url"
+    $_CURL --user-agent "$USER_AGENT" -H "$_H1" -H "$_H2" -H "$_H3" -H "$_H4" -H "$_H5" "$url"
   fi
   ret=$?
   if [ "$ret" != "0" ]; then
-- 
2.52.0