Fix the bug: Fail to create text files that contain multibyte

characters in filemanager, for exmaple, files that contain Chinese
characters.

Reason for producing the bug: One parameter of "fwrite"
is "strlen ($data['content'])". To multibyte character, "strlen" can
not return its actual length. So "fwrite" cannot write all characters
to the created file.

phpgwapi/inc/class.vfs_sql.inc.php

@@ -902,7 +902,7 @@
 			{
 				if ($fp = fopen ($p->real_full_path, 'wb'))
 				{
-					fwrite ($fp, $data['content'], strlen ($data['content']));
+					fwrite ($fp, $data['content']);
 					fclose ($fp);
 					$write_ok = 1;
 				}