[patch] fix macro in a gettexted string

Hello,

I found a macro in a gettexted string which breaks the scanner.

[[[
Fix spelling error in svnadmin message and make gettext-friendly

* subversion/svnadmin/svnadmin.c
  (sub_main) fix spelling, fix macro call breaking gettext
]]]

I would like to point out that the message contains SVN_VER_PATCH as
part of SVN_VER_NUM.
"Cannot guarantee compatibility beyond the current running version (1.8.0)"
Considering the compatibility and versioning scheme used for
repositories, any repository created with 1.8.x can actually be expected
to work with any other 1.8.x. I am not sure how this lines up with the
usage of svn_version__at_least which includes SVN_VER_PATCH and
compatible_version->patch in the comparison, and the message given to
the user.

Andreas