This problem does not exist on Debian 5.0 (I realize you wanted to check Ubuntu 10.04):
batrick@batbytes:~$ ssh -v OpenSSH_5.1p1 Debian-5, OpenSSL 0.9.8g 19 Oct 2007
batrick@batbytes:~$ ssh -i /home/batrick/.ssh/id_rsa.subversion <email address hidden> svnserve -t ( success ( 2 2 ( ) ( edit-pipeline svndiff1 absent-entries commit-revprops depth log-revprops partial-replay ) ) ) quit
(I confirmed through debug output it doesn't attempt authentication using .ssh/id_rsa.) This version of ssh is 5.1 versus 5.5 on Ubuntu 10.10:
batrick@neverwinter:~$ ssh -v OpenSSH_5.5p1 Debian-4ubuntu4, OpenSSL 0.9.8o 01 Jun 2010
This problem does not exist on Debian 5.0 (I realize you wanted to check Ubuntu 10.04):
batrick@batbytes:~$ ssh -v
OpenSSH_5.1p1 Debian-5, OpenSSL 0.9.8g 19 Oct 2007
batrick@batbytes:~$ ssh -i /home/batrick/ .ssh/id_ rsa.subversion <email address hidden> svnserve -t
( success ( 2 2 ( ) ( edit-pipeline svndiff1 absent-entries commit-revprops depth log-revprops partial-replay ) ) ) quit
(I confirmed through debug output it doesn't attempt authentication using .ssh/id_rsa.) This version of ssh is 5.1 versus 5.5 on Ubuntu 10.10:
batrick@ neverwinter: ~$ ssh -v
OpenSSH_5.5p1 Debian-4ubuntu4, OpenSSL 0.9.8o 01 Jun 2010