removed extraneous error message from Upload lib on failure of validate_upload_path()

http://codeigniter.com/bug_tracker/bug/4390/
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 0fc38dc..317cf95 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -144,7 +144,7 @@
 		// Is the upload path valid?

 		if (! $this->validate_upload_path())

 		{

-			$this->set_error('upload_no_filepath');

+			// errors will already be set by validate_upload_path() so just return FALSE

 			return FALSE;

 		}

 						

diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index eef799f..de289f7 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -126,6 +126,7 @@
 	<li>Fixed an AR bug with or_where_not_in() (#4171).</li>

 	<li>Fixed a bug in the FTP library where delete_dir() was not working recursively (#4215).</li>

 	<li>Fixed a Validation bug when set_rules() is used with a non-array field name and rule (#4220).</li>

+	<li>Fixed a bug in the Upload library that might output the same error twice (#4390).</li>

 	<li>Fixed an AR bug when joining with a table alias and table prefix (#4400).</li>

 	<li>Fixed a bug in DB Forge, when inserting an id field (#3456).</li>

 	<li>Fixed a bug in the DB class testing the $params argument.</li>