Fix SQL error in plugin_history.

Since merging s9y#665 `serendipity_plugin_history`
breaks with a SQL error message on every archive
page but the first one; see s9y#693 for reason
and context.

Unset `$serendipity['GET']['page']` before
calling `serendipity_fetchEntries(`)` (and
reset afterwards) to fix that. That's the
correct way, I think, as
`serendipity_fetchEntries()` is not called
in page context here.

Signed-off-by: Thomas Hochstein <thh@inter.net>

plugins/serendipity_plugin_history/serendipity_plugin_history.php

@@ -174,12 +174,19 @@ function generate_content(&$title)
         }
 
         $oldLim = $serendipity['fetchLimit'];
+        if (isset($serendipity['GET']['page'])) {
+            $oldPage = $serendipity['GET']['page'];
+            unset($serendipity['GET']['page']);
+        }
         $nowts = serendipity_serverOffsetHour();
         $maxts = mktime(23, 59, 59,  date('m', $nowts), date('d', $nowts), date('Y', $nowts));
         $mints = mktime(0, 0, 0, date('m', $nowts), date('d', $nowts), date('Y', $nowts));
         $e     = serendipity_fetchEntries(array(($mints-$max_age*86400),
                                             ($maxts-$min_age*86400)), $full, $max_entries);
         $serendipity['fetchLimit'] = $oldLim;
+        if (isset($oldPage)) {
+            $serendipity['GET']['page'] = $oldPage;
+        }
         echo (empty($intro)) ? '' : '<div class="serendipity_history_intro">' . $intro . '</div>' . "\n";
 
         if (!is_array($e)) {