[master] include stderr in git pull results and check for error (#2105)

* [master] include stderr in git pull results and check for error

Old result (seems correct but actually failed):
Updating d190f6a..d958bea

Corrected result (includes failure message):
Updating d190f6a..d958bea
error: Your local changes to the following files would be overwritten by merge:
app/fax/fax_log_view.php
Please, commit your changes or stash them before you can merge.

* tab fixes

core/upgrade/index.php

@@ -56,7 +56,7 @@
 		// run source update
 		if ($do["source"] && permission_exists("upgrade_source") && !is_dir("/usr/share/examples/fusionpbx")) {
 			chdir($_SERVER["PROJECT_ROOT"]);
-			exec("git pull", $response_source_update);
+			exec("git pull 2>&1", $response_source_update);
 			$update_failed = true;
 			if (sizeof($response_source_update) > 0) {
 				$_SESSION["response_source_update"] = $response_source_update;
@@ -64,6 +64,11 @@
 					if (substr_count($response_line, "Updating ") > 0 || substr_count($response_line, "Already up-to-date.") > 0) {
 						$update_failed = false;
 					}
+					
+                    			if (substr_count($response_line, "error") > 0) {
+						$update_failed = true;
+						break;
+					}					
 				}
 			}
 			if ($update_failed) {