Rename the "xpt" manifest directive to "interfaces", per bug 568691 comment 66.

netwerk/test/httpserver/jar.mn

@@ -2,5 +2,5 @@
 httpd.jar:
 %  component {54ef6f81-30af-4b1d-ac55-8ba811293e41} components/httpd.js
 %  contract @mozilla.org/server/jshttp;1 {54ef6f81-30af-4b1d-ac55-8ba811293e41}
-%  xpt components/test_necko.xpt
+%  interfaces components/test_necko.xpt
 #endif

xpcom/components/ManifestParser.cpp

@@ -90,7 +90,7 @@ struct ManifestDirective
 static const ManifestDirective kParsingTable[] = {
   { "binary-component", 1, true, false, false,
     &nsComponentManagerImpl::ManifestBinaryComponent, NULL },
-  { "xpt",              1, true, false, false,
+  { "interfaces",       1, true, false, false,
     &nsComponentManagerImpl::ManifestXPT, NULL },
   { "component",        2, true, false, false,
     &nsComponentManagerImpl::ManifestComponent, NULL },