Move the extern "C" at the right place.

This commit was SVN r11324.

opal/util/trace.h

@@ -30,10 +30,6 @@
 
 #include "opal/util/output.h"
 
-#if defined(c_plusplus) || defined(__cplusplus)
-extern "C" {
-#endif
-
 #define OPAL_TRACE(verbose) \
     do {                                                                       \
         opal_output_verbose(verbose, opal_trace_handle, "TRACE: %s @ %s:%d",   \
@@ -60,6 +56,10 @@ extern "C" {
 
 #endif /* ENABLE_TRACE */
 
+#if defined(c_plusplus) || defined(__cplusplus)
+extern "C" {
+#endif
+
 extern int opal_trace_handle;
 
 OPAL_DECLSPEC void opal_trace_init(void);