Fix link to documentation and bconsole typo

[thraizz]

First commit fixes #727: wrong error message in disable schedule
Description: Disabling a non-existent schedule over bconsole no longer
throws "Client not found" error, now it is "Schedule not found"

Second commit fixes a documentation link mentioned here, where a fuzzy directory structure would throw a non-existent link.

[joergsteffens]

The second patch is not required. The existing link works now.

The first patch is good, but please adapt the commit message to common practice.

[thraizz]

Done, sorry for the delay. Also rewrote the commit message so that the fix is more obvious.

[joergsteffens]

Unfortunately, this commit message is still not like requested.
If this references a https://bugs.bareos.org ticket, it should look like:

    bugfix: prevents file corruptions by SHA1
    
    Fixes a bug when using SHA1 file signatures in Bareos version compiled
    without openssl.
    
    Fixes #838: File corruption with SHA1 signature

This way, the bug in https://bugs.bareos.org is automatically closed and refers to the change.

Please adapt your commit message.

As the source have been moved to the core subdirectory, please rebase your commit onto master.

[thraizz]

I rebased and changed both the commit message as well as the bugfix itself, so that it matches the new style how error messages are written in ua_cmds.cc.