Fixing blackhole support in libmysqld

libmysqld/Makefile.am:
  Adding ha_blackhole.cc

libmysqld/Makefile.am

@@ -58,7 +58,8 @@ sqlsources = derror.cc field.cc field_conv.cc strfunc.cc filesort.cc \
 	sql_string.cc sql_table.cc sql_test.cc sql_udf.cc \
 	sql_update.cc sql_yacc.cc table.cc thr_malloc.cc time.cc \
 	unireg.cc uniques.cc stacktrace.c sql_union.cc hash_filo.cc \
-	spatial.cc gstream.cc sql_help.cc tztime.cc
+	spatial.cc gstream.cc sql_help.cc tztime.cc \
+	ha_blackhole.cc
 
 libmysqld_int_a_SOURCES= $(libmysqld_sources) $(libmysqlsources) $(sqlsources) $(sqlexamplessources)
 libmysqld_a_SOURCES=