Fall back to default color for undefined severity/resolution

Fixes system notices when using customized enums having values not
defined in the plugin's configuration (board_severity_colors and
board_resolution_colors).

Undefined values are displayed in white.

Author: dregad

Scrum/pages/board.php

@@ -323,8 +323,8 @@
 <p class="scrumstatus"><?php echo get_enum_element("status", $status) ?></p>
 <?php endif ?>
 <?php if (isset($bugs[$status])) foreach ($bugs[$status] as $bug):
-$sevcolor = $sevcolors[$bug->severity];
-$rescolor = $rescolors[$bug->resolution];
+$sevcolor = array_key_exists($bug->severity, $sevcolors) ? $sevcolors[$bug->severity] : "white";
+$rescolor = array_key_exists($bug->resolution, $rescolors) ? $rescolors[$bug->resolution] : "white";
 ?>
 
 <div class="scrumblock">