Add missing include

This commit was SVN r32406.

opal/runtime/opal_init.c

@@ -49,6 +49,7 @@
 #if OPAL_ENABLE_FT_CR    == 1
 #include "opal/mca/compress/base/base.h"
 #endif
+#include "opal/threads/threads.h"
 
 #include "opal/runtime/opal_cr.h"
 #include "opal/mca/crs/base/base.h"