Fix possible NPE reported by FindBugs.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1495269 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

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

@@ -86,7 +86,13 @@ Token nextToken(final Token token) throws IOException {
         }
 
         if (isStartOfLine(lastChar) && isCommentStart(c)) {
-            final String comment = in.readLine().trim();
+            String line = in.readLine();
+            if (line == null) {
+                token.type = EOF;
+                // don't set token.isReady here because no content
+                return token;                
+            }
+            final String comment = line.trim();
             token.content.append(comment);
             token.type = COMMENT;
             return token;