Don't allow to set same command sections in the configuration

[chemamartinez]

No error is shown when it is set two same <command> tags for active-response in the configuration file. For example:

<command>
    <name>disable-account</name>
    <executable>disable-account.sh</executable>
    <expect>user</expect>
    <timeout_allowed>yes</timeout_allowed>
  </command>

  <command>
    <name>disable-account</name>
    <executable>disable-account.sh</executable>
    <expect>user</expect>
    <timeout_allowed>yes</timeout_allowed>
  </command>

However, only the first one works so it should not be allowed to set two commands with the same name or at least it should trigger a warning message.

[vikman90]

This issue is a duplicate of #1057
Fixed in #1128