Assume UTF8 for HTML (2)

app/src/main/java/com/sun/mail/handlers/text_plain.java

@@ -146,10 +146,10 @@ public class text_plain extends handler_base {
 	    String charset = ct.getParameter("charset");
 	    if (charset == null)
 		// If the charset parameter is absent, use US-ASCII.
-	    if ("text/html".equalsIgnoreCase(ct.getBaseType()))
+		charset = "us-ascii";
+		if ("us-ascii".equals(charset) &&
+				"text/html".equalsIgnoreCase(ct.getBaseType()))
 			charset = StandardCharsets.UTF_8.name();
-	    else
-			charset = "us-ascii";
 	    return MimeUtility.javaCharset(charset);
 	} catch (Exception ex) {
 	    return null;