Revert "shutdown trigger select" on Darwin.

Fixed daemon shutdown on Darwin without "MHD_USE_PIPE_FOR_SHUTDOWN" option.

ChangeLog

@@ -1,3 +1,7 @@
+Sat Apr 23 14:17:15 CET 2016
+	Revert "shutdown trigger select" on Darwin. Fixed daemon shutdown
+	on Darwin without "MHD_USE_PIPE_FOR_SHUTDOWN" option. -EG
+
 Fri Apr 22 14:29:28 CET 2016
 	Fixed race conditions when stopping quiesced daemon with thread
 	pool. -EG

configure.ac

@@ -148,7 +148,6 @@ case "$host_os" in
      AC_DEFINE_UNQUOTED(OSX,1,[This is an OS X system])
      CFLAGS="-no-cpp-precomp -fno-common $CFLAGS"
      mhd_host_os='Darwin'
-     shutdown_trig_select='yes'
      AC_MSG_RESULT([[$mhd_host_os]])
      ;;
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