test-log: also test "log -p -R" case

tests/test-log

@@ -185,4 +185,9 echo '% log -p --cwd dir (in subdir)'
 mkdir dir
 hg log -p --cwd dir
 
+echo '% log -p -R repo'
+cd dir
+hg log -p -R .. ../a
+
+
 exit 0

tests/test-log.out

@@ -514,3 +514,15 diff -r 000000000000 -r 24427303d56f a
 @@ -0,0 +1,1 @@
 +a
 
+% log -p -R repo
+changeset:   0:24427303d56f
+user:        test
+date:        Thu Jan 01 00:00:00 1970 +0000
+summary:     commit on default
+
+diff -r 000000000000 -r 24427303d56f a
+--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
++++ b/a	Thu Jan 01 00:00:00 1970 +0000
+@@ -0,0 +1,1 @@
++a
+