[Samba] Samba 4 git pull error

[steve]

steve at hh3:~/samba-master> git pull
Updating bfc7481..e32ad9b
error: Your local changes to the following files would be overwritten by 
merge:
     auth/common_auth.h
     auth/credentials/credentials_ntlm.c
     auth/credentials/credentials_samba3.c
<snip>
     source3/lib/util_cmdline.c
     source3/libads/dns.c
     source3/libads/k
Aborting

I haven't changed any files under samba-master. I have a backup of 
/usr/local/samba and samba-master. Do I delete and start again?
Thanks,
Steve