Revert TXT add update

The change was needed for Power-Mailinabox and broke Mail-in-a-box, so a new API for Power-Mailinabox has been added

dnsapi/dns_miab.sh

@@ -16,8 +16,7 @@ Author: Darven Dissek, William Gertz
 #Usage: dns_miab_add  _acme-challenge.www.domain.com  "XKrxpRBosdIKFzxW_CT3KLZNf6q0HG9i01zxXp5CPBs"
 dns_miab_add() {
   fulldomain=$1
-  # Added "value=" and "&ttl=300" to accomodate the new TXT record format used by the MIAB/PMIAB API
-  txtvalue="value=$2&ttl=300"
+  txtvalue=$2
   _info "Using miab challenge add"
   _debug fulldomain "$fulldomain"
   _debug txtvalue "$txtvalue"