Update .arcconfig and acknowledge that we're the new maintainers in X…

…HProf

Summary: Modernize this stuff a bit.

Test Plan: Ran `arc diff` to produce this diff. Read `CREDITS`.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10366

.arcconfig

@@ -1,6 +1,3 @@
 {
-  "project_id" : "xhprof",
-  "conduit_uri" : "https://secure.phabricator.com/",
-  "remote_hooks_installed" : true,
-  "copyright_holder" : "Facebook, Inc."
-}
+  "phabricator.uri": "https://secure.phabricator.com/"
+}

CREDITS

@@ -1,5 +1,7 @@
 Originally developed at Facebook, XHProf was open sourced in Mar, 2009.
 
+XHProf is now maintained by Phacility.
+
 Creators:
   Changhao Jiang
   Kannan Muthukkaruppan
@@ -9,4 +11,3 @@ Creators:
 Additional Contributors:
   George Cabrera      - UI enhancements
   Paul Saab           - FreeBSD port
-