[folks] Don't print out a stacktrace when an error message is empty.

[Travis Reitter <treitter src gnome org>]

commit 73e7a6342455daedae51628761a843117c6cc772
Author: Travis Reitter <travis reitter collabora co uk>
Date:   Mon Jan 17 15:47:46 2011 -0800

    Don't print out a stacktrace when an error message is empty.
    
    This was printing a lot of stacktraces for non-errors from GConf.

 tests/lib/test-case.vala |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/tests/lib/test-case.vala b/tests/lib/test-case.vala
index 4286df9..9e1c4e9 100644
--- a/tests/lib/test-case.vala
+++ b/tests/lib/test-case.vala
@@ -80,8 +80,10 @@ public abstract class Folks.TestCase : Object
 
       private void _printerr_func_stack_trace (string? text)
         {
-          if (text != null)
-            stderr.printf (text);
+          if (text == null || str_equal (text, ""))
+            return;
+
+          stderr.printf (text);
 
           /* Print a stack trace since we've hit some major issue */
           GLib.on_error_stack_trace ("libtool --mode=execute gdb");