Fixes preferences master password handling

app/view/preferences/PreferencesController.js

@@ -13,12 +13,28 @@ Ext.define('Rambox.view.preferences.PreferencesController', {
 
 		var values = me.getView().down('form').getForm().getFieldValues();
 
-		// Master Password
-		if ( values.master_password && (Ext.isEmpty(values.master_password1) || Ext.isEmpty(values.master_password2)) ) return;
-		if ( values.master_password && (values.master_password1 !== values.master_password2) ) return;
-		if ( values.master_password ) values.master_password = Rambox.util.MD5.encypt(values.master_password1);
+		// master password activated and only one of the fields "password" or "password confirmation" filled
+		if (values.master_password === true &&
+			(Ext.isEmpty(values.master_password1) === false && Ext.isEmpty(values.master_password2) === true ||
+			Ext.isEmpty(values.master_password1) === true && Ext.isEmpty(values.master_password2) === false)) return;
+
+		// password and confirmation don't match
+		if (values.master_password === true && (values.master_password1 !== values.master_password2)) return;
+
+		// master password activated and changed
+		if (values.master_password === true &&
+			Ext.isEmpty(values.master_password1) === false &&
+			Ext.isEmpty(values.master_password2) === false) {
+
+			values.master_password = Rambox.util.MD5.encypt(values.master_password1);
 			delete values.master_password1;
 			delete values.master_password2;
+		}
+
+		// prevent overwriting password when unchanged
+		if (values.master_password === true) {
+			delete values.master_password;
+		}
 
 		// Proxy
 		if ( values.proxy && (Ext.isEmpty(values.proxyHost) || Ext.isEmpty(values.proxyPort)) ) return;