This PR is a proposal to fix #1609

As per #1609 it is not possible to retrieve errors from Augeas if it is
failing. This PR adds a new command to be able to retrieve them.

I have not added a test, as there are currently no tests at all for the
Augeas command.

I thought about automatically retrieving and adding any error
information to a failing Augeas command, but I decided that is
over-engineering things too much and that a developer should decide how
they want to handle errors and retrieve them manually if they wish to.

Please review and merge, or let me know how to improve it further.

lib/Rex/Commands/Augeas.pm

@@ -369,6 +369,25 @@ Returns the value of the given item.
     }
   }
 
+=item errors
+
+Returns any errors from a previous command (uses the augeas "errors" command)
+
+ my $errors = augeas "errors"
+
+=cut
+
+  elsif ( $action eq "errors" ) {
+
+    if ( $is_ssh || !$has_config_augeas ) {
+      my $result = _run_augtool("errors");
+      return $result->{return};
+    }
+    else {
+      return $aug->error_details;
+    }
+  }
+
   else {
     Rex::Logger::info("Unknown augeas action.");
   }