THRIFT-2300 D configure info output should follow same format as other languages

Patch: David Nadlinger
diff --git a/configure.ac b/configure.ac
index 9dd0e2d..6ce4aca 100755
--- a/configure.ac
+++ b/configure.ac
@@ -678,9 +678,10 @@
 fi
 if test "$have_d" = "yes" ; then
   echo
-  echo "Using D Compiler ............. : $DMD"
-  echo "Building D libevent tests .... : $with_d_event_tests"
-  echo "Building D SSL tests ......... : $with_d_ssl_tests"
+  echo "D Library:"
+  echo "   Using D Compiler .......... : $DMD"
+  echo "   Building D libevent tests . : $with_d_event_tests"
+  echo "   Building D SSL tests ...... : $with_d_ssl_tests"
 fi
 echo
 echo "If something is missing that you think should be present,"