svncommands: fix layering violation & tweak error messages. Importing `SubversionException' directly from `svn.core' is a layering violation: Anything within the Subversion bindings should only be accessed via svnwrap. The advantages to doing this are twofold: we only need to intercept missing bindings in one place, and we have the option of supporting alternate bindings. As an added bonus, the recently-added support for intercepting missing Subversion bindings actually works. Two error messages are tweaked to remove `It appears...' from one error message (just blaming Subversion instead) and make both errors include the URL in the suggested command line.

#!/bin/sh
mkdir temp || exit 1
cd temp
svnadmin create repo
svn co file://`pwd`/repo wc
pushd wc
mkdir -p project/trunk
svn add project
svn ci -m 'trunk'
cd project/trunk
echo a > a
mkdir narf
svn add a narf
svn ci -m 'file and empty dir'
popd
svnadmin dump repo > ../empty_dir_in_trunk_not_repo_root.svndump
echo 'dump in empty_dir_in_trunk_not_repo_root.svndump'
echo 'you can probably delete temp now'