Fix a divide by zero bug in PaginationHelper.php, a=chris

diff --git a/src/views/helpers/PaginationHelper.php b/src/views/helpers/PaginationHelper.php
index fa2560845..d4e9228ab 100755
--- a/src/views/helpers/PaginationHelper.php
+++ b/src/views/helpers/PaginationHelper.php
@@ -46,7 +46,12 @@ class PaginationHelper extends Helper
      * @var int
      */
     const MAX_PAGES_TO_SHOW = 10;
-
+    /**
+     * The maximum numbered links to pages to show besides the next and
+     * previous links
+     * @var int
+     */
+    const MIN_RESULTS_PER_PAGE = 10;
     /**
      * Draws a strip of links which begins with a previous
      * link (if their are previous pages of links) followed by up to
@@ -58,7 +63,8 @@ class PaginationHelper extends Helper
      * @param int $limit the number of the first link to display in the
      *     set of search results.
      * @param int $results_per_page   how many links are displayed on a given
-     *     page of search results
+     *     page of search results. The minimum value of this is
+     *     self::MIN_RESULTS_PER_PAGE
      * @param int $total_results the total number of search results for the
      *     current search term
      * @param bool $micro whether to make a tiny pagination rather than normal
@@ -72,6 +78,7 @@ class PaginationHelper extends Helper
         if ($_SERVER["MOBILE"] && $micro) {
             return;
         }
+        $results_per_page = max(self::MIN_RESULTS_PER_PAGE, $results_per_page);
         $no_follow = ($no_follow) ? " rel='nofollow' " : "";
         $num_earlier_pages = ceil($limit/$results_per_page);
         $total_pages = ceil($total_results/$results_per_page);