remove DEFAULT_DNS_SLEEP.

fix https://github.com/acmesh-official/acme.sh/issues/2773

acme.sh

@@ -48,7 +48,6 @@ LOCAL_ANY_ADDRESS="0.0.0.0"
 
 DEFAULT_RENEW=60
 
-DEFAULT_DNS_SLEEP=120
 
 NO_VALUE="no"
 
@@ -6223,7 +6222,7 @@ Parameters:
   --stateless                       Use stateless mode, see: $_STATELESS_WIKI
   --apache                          Use apache mode.
   --dns [dns_cf|dns_dp|dns_cx|/path/to/api/file]   Use dns mode or dns api.
-  --dnssleep  [$DEFAULT_DNS_SLEEP]                  The time in seconds to wait for all the txt records to take effect in dns api mode. Default $DEFAULT_DNS_SLEEP seconds.
+  --dnssleep   300                  The time in seconds to wait for all the txt records to take effect in dns api mode. It's not necessary to use this by default, $PROJECT_NAME polls dns status automatically.
 
   --keylength, -k [2048]            Specifies the domain key length: 2048, 3072, 4096, 8192 or ec-256, ec-384, ec-521.
   --accountkeylength, -ak [2048]    Specifies the account key length: 2048, 3072, 4096