run-tests: fix _checkhglib() so it's correct when using --with-hg.
Since this makes the warning less likely, upgrade it to a "real"
warning to stderr.
adding a
0: a
hg: unknown command 'an'
Mercurial Distributed SCM
basic commands:
add add the specified files on the next commit
annotate show changeset information per file line
clone make a copy of an existing repository
commit commit the specified files or all outstanding changes
diff diff repository (or selected files)
export dump the header and diffs for one or more changesets
init create a new repository in the given directory
log show revision history of entire repository or files
merge merge working directory with another revision
parents show the parents of the working directory or revision
pull pull changes from the specified source
push push changes to the specified destination
remove remove the specified files on the next commit
serve export the repository via HTTP
status show changed files in the working directory
update update working directory
use "hg help" for the full list of commands or "hg -v" for details
0: a
% should succeed - up is an alias, not an abbreviation
0 files updated, 0 files merged, 0 files removed, 0 files unresolved