We can do better when reporting the status of one-liner script execution.

Change the prototype of ScriptInterpreter::ExecuteOneLine() to return bool
instead of void and take one additional parameter as CommandReturnObject *.

Propagate the status of one-liner execution back appropriately.

llvm-svn: 109899
diff --git a/lldb/test/command_source/TestCommandSource.py b/lldb/test/command_source/TestCommandSource.py
index 979f95c..45611f4 100644
--- a/lldb/test/command_source/TestCommandSource.py
+++ b/lldb/test/command_source/TestCommandSource.py
@@ -21,6 +21,8 @@
         self.assertTrue(res.Succeeded())
 
         self.ci.HandleCommand("script my.date()", res)
+        if (not res.Succeeded()):
+            print res.GetError()
         self.assertTrue(res.Succeeded())
 
         time.sleep(1)