git-svn testsuite: use standard configuration for Subversion tools

I have tweaked configuration in my ~/.subversion directory, namely I am
running auto-properties and automatically adding '$Id$' expansion to
every file.  This choke the last test named 'proplist' from
t9101-git-svn-props.sh, because one more property, svn:keywords is
automatically added.

I had just wrapped svn invocation with the svn_cmd that specifies empty
directory via --config-dir argument.  Since the latter is the global
option, it should be recognized by all svn subcommands, so no
regressions will be introduced.

Now svn_cmd is used everywhere, not just in the failed test module: this
should guard us from the future clashes with user-defined configuration
tweaks.

Signed-off-by: Eygene Ryabinkin <rea-git@codelabs.ru>
Acked-by: Eric Wong <normalperson@yhbt.net>

t/t9105-git-svn-commit-diff.sh

@@ -8,7 +8,7 @@ test_expect_success 'initialize repo' '
 	mkdir import &&
 	cd import &&
 	echo hello > readme &&
-	svn import -m "initial" . "$svnrepo" &&
+	svn_cmd import -m "initial" . "$svnrepo" &&
 	cd .. &&
 	echo hello > readme &&
 	git update-index --add readme &&
@@ -27,16 +27,16 @@ prev=`git rev-parse --verify HEAD^1`
 test_expect_success 'test the commit-diff command' '
 	test -n "$prev" && test -n "$head" &&
 	git svn commit-diff -r1 "$prev" "$head" "$svnrepo" &&
-	svn co "$svnrepo" wc &&
+	svn_cmd co "$svnrepo" wc &&
 	cmp readme wc/readme
 	'
 
 test_expect_success 'commit-diff to a sub-directory (with git svn config)' '
-	svn import -m "sub-directory" import "$svnrepo"/subdir &&
+	svn_cmd import -m "sub-directory" import "$svnrepo"/subdir &&
 	git svn init --minimize-url "$svnrepo"/subdir &&
 	git svn fetch &&
 	git svn commit-diff -r3 "$prev" "$head" &&
-	svn cat "$svnrepo"/subdir/readme > readme.2 &&
+	svn_cmd cat "$svnrepo"/subdir/readme > readme.2 &&
 	cmp readme readme.2
 	'