Fix the documentation about default value of captcha_cmd option

diff --git a/doc/guide.tex b/doc/guide.tex
index f13c58884103bc32226f2c18e8fa2aea1c90f15c..9c1590fb37f437aa285aa1d260693761634c188e 100644 (file)
--- a/doc/guide.tex
+++ b/doc/guide.tex
@@ -1664,7 +1664,7 @@ The configurable options are:
 \begin{description}
   \titem{\{captcha\_cmd, Path\}} 
   Full path to a script that generates the image.
-  The default value is an empty string: \term{""}
+  The default value disables the feature: \term{undefined}
   \titem{\{captcha\_host, ProtocolHostPort\}} 
   ProtocolHostPort is a string with the host, and optionally the Protocol and Port number.
   It must identify where ejabberd listens for CAPTCHA requests.