Re-introduce DISABLED but as a private constant; only needed for PRISTINE definition

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1398559 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/csv/CSVFormat.java

@@ -41,6 +41,13 @@ public class CSVFormat implements Serializable {
 
     private static final long serialVersionUID = 1L;
 
+    /**
+     * Constant char to use for disabling comments, escapes and encapsulation. The value -2 is used because it
+     * won't be confused with an EOF signal (-1), and because the Unicode value {@code FFFE} would be encoded as two chars
+     * (using surrogates) and thus there should never be a collision with a real text char.
+     */
+    private static final char DISABLED = '\ufffe';
+
     private final char delimiter;
     private final Character quoteChar;
     private final Quote quotePolicy;