py/dnsserver: TXTRecord copes with single strings

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

python/samba/dnsserver.py

@@ -241,6 +241,8 @@ class TXTRecord(dnsserver.DNS_RPC_RECORD):
         self.dwFlags = rank | node_flag
         self.dwSerial = serial
         self.dwTtlSeconds = ttl
+        if isinstance(slist, str):
+            slist = [slist]
         names = []
         for s in slist:
             name = dnsserver.DNS_RPC_NAME()