Revert "re-introduce BUG #3258 to test CI fails correctly"

This reverts commit 8e3c0a5.

Author: terhorstd

models/iaf_bw_2001.cpp

@@ -23,6 +23,7 @@
 #include "iaf_bw_2001.h"
 
 #ifdef HAVE_GSL
+#ifdef HAVE_BOOST
 
 // Includes from libnestutil:
 #include "dict_util.h"
@@ -521,4 +522,5 @@ nest::iaf_bw_2001::handle( CurrentEvent& e )
     e.get_rel_delivery_steps( kernel().simulation_manager.get_slice_origin() ), e.get_weight() * e.get_current() );
 }
 
+#endif // HAVE_BOOST
 #endif // HAVE_GSL