bees: limit FD cache size explicitly

This will allow the default size limit for cache objects to be changed
with impunity.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
(cherry picked from commit 9daa51edaa)

src/bees-context.cc

@@ -35,6 +35,7 @@ BeesFdCache::BeesFdCache()
 		BEESCOUNTADD(open_ino_ms, open_timer.age() * 1000);
 		return rv;
 	});
+	m_file_cache.max_size(BEES_FD_CACHE_SIZE);
 }
 
 Fd