Unable to access gcc svn.

[Ed Smith-Rowland <3dw4rd at verizon dot net>]

I recently upgraded to Ubuntu Xenial and my because the supported 
OpenSSH no longer supports DSA my gnu keys no longer work.

Trying to fix it involved so many false starts that I am now blocked:

ed@bad-horse:~$ svn update gcc
Updating 'gcc':
Received disconnect from 209.132.180.131 port 22:2: Too many 
authentication failures for emsr
Connection to gcc.gnu.org closed by remote host.
svn: E170013: Unable to connect to a repository at URL 
'svn+ssh://emsr@gcc.gnu.org/svn/gcc/trunk'
svn: E210002: To better debug SSH connection problems, remove the -q 
option from 'ssh' in the [tunnels] section of your Subversion 
configuration file.
svn: E210002: Network connection closed unexpectedly
ed@bad-horse:~$

I would like to be unlocked and to register this key only:
ssh-rsa 
AAAAB3NzaC1yc2EAAAADAQABAAABAQDCJHxK+znyU4A1gKsFE18bL+3lEyzXZOo+peBDJF/PKpJrBvQY2DW85UNH3SJmmIfypc4th5RiSNjZJLiKKclUYmnTa75L5N1V2X3d5w1Axx0LM9/2GDkLZLdsXRCmGQ5Dr0UWdxCws8JPV5Sb/+RiEr5HcInnggX7vzhiWTCxaoRYIgtJJoEosfuYNHIZ9JEIvAyPm/cc0dC2t/1a2GPlJK0e+0xdwij3zD19a0vUGtddHdPZISZCWhhMLLvp2F4ZPuVrPrzdz55VoBvik/eDO29WvulRGcsoasCkmHYJsbJtUlHjYYFymte/mSkSYaAsQA0ZgMZFrnB9ylAe3Wrd 
ed@bad-horse

If, after unlocking, there's a page or webform that will allow me to 
manage ssh keys point me there and I'll set my own keys.

Thanks,

Ed Smith-Rowland
libstdc++ and C++ maintainer.
Sad Ubuntu user.