[1870] removed unnecessary call to AX_BOOST_INCLUDE.

since AC_REQUIRE internally does it.

examples/m4/ax_isc_bind10.m4

@@ -26,8 +26,6 @@ AC_REQUIRE([AX_BOOST_INCLUDE])
 AC_LANG_SAVE
 AC_LANG([C++])
 
-AX_BOOST_INCLUDE
-
 # Check for BIND10 common headers
 
 AC_ARG_WITH(bind10-include,