switch to dbStats, only display fileSize if it exists

src/database/mongo.js

@@ -182,7 +182,7 @@
 				db.command({'serverStatus': 1}, next);
 			},
 			stats: function(next) {
-				db.stats({}, next);
+				db.command({'dbStats': 1}, next);
 			},
 			listCollections: function(next) {
 				db.listCollections().toArray(function(err, items) {

src/views/admin/advanced/database.tpl

@@ -16,7 +16,9 @@
 					<span>Data Size</span> <span class="text-right">{mongo.dataSize} mb</span><br/>
 					<span>Storage Size</span> <span class="text-right">{mongo.storageSize} mb</span><br/>
 					<span>Index Size</span> <span class="text-right">{mongo.indexSize} mb</span><br/>
+					<!-- IF mongo.fileSize -->
 					<span>File Size</span> <span class="text-right">{mongo.fileSize} mb</span><br/>
+					<!-- ENDIF mongo.fileSize -->
 					<hr/>
 					<span>Resident Memory</span> <span class="text-right">{mongo.mem.resident} mb</span><br/>
 					<span>Virtual Memory</span> <span class="text-right">{mongo.mem.virtual} mb</span><br/>