trivial: use StringBuilder in place of StringBuffer

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/fileupload/trunk@1456973 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/fileupload/util/mime/MimeUtility.java b/src/main/java/org/apache/commons/fileupload/util/mime/MimeUtility.java
index ab30c5b..776423e 100644
--- a/src/main/java/org/apache/commons/fileupload/util/mime/MimeUtility.java
+++ b/src/main/java/org/apache/commons/fileupload/util/mime/MimeUtility.java
@@ -84,7 +84,7 @@
         int startWhiteSpace = -1;
         int endWhiteSpace = -1;
 
-        StringBuffer decodedText = new StringBuffer(text.length());
+        StringBuilder decodedText = new StringBuilder(text.length());
 
         boolean previousTokenEncoded = false;