git-svn: ignore leading blank lines in svn:ignore

Subversion ignores all blank lines in svn:ignore properties.  The old
git-svn code ignored blank lines everywhere except for the first line
of the svn:ignore property.  This patch makes the "git svn
show-ignore" and "git svn create-ignore" commands ignore leading blank
lines, too.

Also include leading blank lines in the test suite.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Acked-by: Eric Wong <normalperson@yhbt.net>
diff --git a/t/t9101-git-svn-props.sh b/t/t9101-git-svn-props.sh
index 9da4178..929499e 100755
--- a/t/t9101-git-svn-props.sh
+++ b/t/t9101-git-svn-props.sh
@@ -142,7 +142,9 @@
 	touch deeply/nested/directory/.keep &&
 	svn_cmd add deeply &&
 	svn_cmd up &&
-	svn_cmd propset -R svn:ignore 'no-such-file*' .
+	svn_cmd propset -R svn:ignore '
+no-such-file*
+' .
 	svn_cmd commit -m 'propset svn:ignore'
 	cd .. &&
 	git svn show-ignore > show-ignore.got &&
@@ -171,6 +173,7 @@
 	"
 
 cat >prop.expect <<\EOF
+
 no-such-file*
 
 EOF