file_key_management plugin should be disabled by default when linked statically

When file_key_management plugin is linked statically, it is enabled by default, which of course causes ugly (even though non-fatal) errors on bootstrap and server startup, because the plugin is not configured.
It should either be disallowed to link it statically at all, or it should be disabled by default, something similar to feedback plugin

diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc

index 6d8268e..1d2e2d8 100644

--- a/sql/sql_plugin.cc

+++ b/sql/sql_plugin.cc

@@ -211,6 +211,7 @@

   /* we disable few other plugins by default */

   ,{ "feedback", PLUGIN_OFF }

+  ,{ "file_key_management", PLUGIN_OFF }

 };

 /* support for Services */