Fix comments about X.509 versions
diff --git a/include/polarssl/x509_csr.h b/include/polarssl/x509_csr.h
index bbe6bec..6591e38 100644
--- a/include/polarssl/x509_csr.h
+++ b/include/polarssl/x509_csr.h
@@ -56,7 +56,7 @@
     x509_buf raw;           /**< The raw CSR data (DER). */
     x509_buf cri;           /**< The raw CertificateRequestInfo body (DER). */
 
-    int version;
+    int version;            /**< CSR version (1=v1). */
 
     x509_buf  subject_raw;  /**< The raw subject data (DER). */
     x509_name subject;      /**< The parsed subject data (named information object). */