Change CommandReturnObject::AppendMessage to print an empty line if

AppendMessage("") is called.  This idiom is used in a handful of places
right now (e.g. to put space between different threads in 'bt all') but
the empty newline is being omitted instead of emitted.
<rdar://problem/13753830> 

llvm-svn: 180841

lldb/source/Interpreter/CommandReturnObject.cpp

@@ -106,7 +106,7 @@ CommandReturnObject::AppendWarningWithFormat (const char *format, ...)
 void
 CommandReturnObject::AppendMessage (const char *in_string)
 {
-    if (!in_string || *in_string == '\0')
+    if (!in_string)
         return;
     GetOutputStream().Printf("%s\n", in_string);
 }