nfs: make headers idempotent

ccanlint did this automatically.

ccan/nfs/LICENSE

+../../licenses/GPL-3
\ No newline at end of file

ccan/nfs/libnfs-private.h

+#ifndef CCAN_NFS_LIBNFS_PRIVATE_H
+#define CCAN_NFS_LIBNFS_PRIVATE_H
 /* 
    Copyright (C) by Ronnie Sahlberg <ronniesahlberg@gmail.com> 2010
    
@@ -66,3 +68,4 @@ int rpc_get_pdu_size(char *buf);
 int rpc_process_pdu(struct rpc_context *rpc, char *buf, int size);
 void rpc_error_all_pdus(struct rpc_context *rpc, char *error);
 
+#endif /* CCAN_NFS_LIBNFS_PRIVATE_H */

ccan/nfs/libnfs-raw.h

+#ifndef CCAN_NFS_LIBNFS_RAW_H
+#define CCAN_NFS_LIBNFS_RAW_H
 /* 
    Copyright (C) by Ronnie Sahlberg <ronniesahlberg@gmail.com> 2010
    
@@ -557,3 +559,4 @@ int rpc_nfs_link_async(struct rpc_context *rpc, rpc_cb cb, struct nfs_fh3 *file,
  */
 int rpc_nfsacl_null_async(struct rpc_context *rpc, rpc_cb cb, void *private_data);
 
+#endif /* CCAN_NFS_LIBNFS_RAW_H */

ccan/nfs/nfs.h

+#ifndef CCAN_NFS_H
+#define CCAN_NFS_H
 /* 
    Copyright (C) by Ronnie Sahlberg <ronniesahlberg@gmail.com> 2010
    
@@ -911,3 +913,4 @@ int nfs_link_sync(struct nfs_context *nfs, const char *oldpath, const char *newp
 
 //qqq replace later with lseek(cur, 0)
 nfs_off_t nfs_get_current_offset(struct nfsfh *nfsfh);
+#endif /* CCAN_NFS_H */