Make PAGE_TIMEOUT configurable in LocalConfig.php, a=chris

diff --git a/src/configs/Config.php b/src/configs/Config.php
index ed1ae6426..15c6a8b79 100755
--- a/src/configs/Config.php
+++ b/src/configs/Config.php
@@ -588,7 +588,9 @@ nsdefine('NUM_MULTI_CURL_PAGES', 100);
 /** number of pages to extract from an archive in one go */
 nsdefine('ARCHIVE_BATCH_SIZE', 100);
 /** time in seconds before we give up on multi page requests*/
-nsdefine('PAGE_TIMEOUT', 30);
+if (!nsdefined('PAGE_TIMEOUT')) {
+    nsdefine('PAGE_TIMEOUT', 30);
+}
 /** time in seconds before we give up on a single page request*/
 nsdefine('SINGLE_PAGE_TIMEOUT', ONE_MINUTE);
 /** max time in seconds in a process before write a log message if