Say in gsql documentation that 'Access Database' capability is required

Since abd6d4e1d4ac11b7478c00289258a462d8544a24 the 'Access Database'
capability is required to run the gsql command.

Change-Id: I39b2b22be975172839ab9808649afcfc58994806
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/Documentation/cmd-gsql.txt b/Documentation/cmd-gsql.txt
index b53670b..7ddc41f 100644
--- a/Documentation/cmd-gsql.txt
+++ b/Documentation/cmd-gsql.txt
@@ -32,7 +32,9 @@
 
 ACCESS
 ------
-Caller must be a member of the privileged 'Administrators' group.
+Caller must have been granted the
+link:access-control.html#capability_accessDatabase[Access Database]
+global capability.
 
 SCRIPTING
 ---------