Fix use of strategy options with interactive rebases

git-rebase.sh wrote strategy options to .git/rebase/merge/strategy_opts
in the following format:
  '--ours'  '--renormalize'
Note the double spaces.

git-rebase--interactive uses sequencer.c to parse that file, and
sequencer.c used split_cmdline() to get the individual strategy options.
After splitting, sequencer.c prefixed each "option" with a double dash,
so, concatenating all its options would result in:
  -- --ours -- --renormalize

So, when it ended up calling try_merge_strategy(), that in turn would run
  git merge-$strategy -- --ours -- --renormalize $merge_base -- $head $remote

instead of the expected/desired
  git merge-$strategy --ours --renormalize $merge_base -- $head $remote

Remove the extra spaces so that when it goes through split_cmdline() we end
up with the desired command line.
Signed-off-by: NElijah Newren <newren@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-rebase.sh

@@ -289,7 +289,7 @@ do
 		do_merge=t
 		;;
 	--strategy-option=*)
-		strategy_opts="$strategy_opts $(git rev-parse --sq-quote "--${1#--strategy-option=}")"
+		strategy_opts="$strategy_opts $(git rev-parse --sq-quote "--${1#--strategy-option=}" | sed -e s/^.//)"
 		do_merge=t
 		test -z "$strategy" && strategy=recursive
 		;;

sequencer.c

@@ -2000,6 +2000,7 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 static void read_strategy_opts(struct replay_opts *opts, struct strbuf *buf)
 {
 	int i;
+	char *strategy_opts_string;
 
 	strbuf_reset(buf);
 	if (!read_oneliner(buf, rebase_path_strategy(), 0))
@@ -2008,7 +2009,11 @@ static void read_strategy_opts(struct replay_opts *opts, struct strbuf *buf)
 	if (!read_oneliner(buf, rebase_path_strategy_opts(), 0))
 		return;
 
-	opts->xopts_nr = split_cmdline(buf->buf, (const char ***)&opts->xopts);
+	strategy_opts_string = buf->buf;
+	if (*strategy_opts_string == ' ')
+		strategy_opts_string++;
+	opts->xopts_nr = split_cmdline(strategy_opts_string,
+				       (const char ***)&opts->xopts);
 	for (i = 0; i < opts->xopts_nr; i++) {
 		const char *arg = opts->xopts[i];
 

t/t3418-rebase-continue.sh

@@ -74,7 +74,7 @@ test_expect_success 'rebase --continue remembers merge strategy and options' '
 	test -f funny.was.run
 '
 
-test_expect_failure 'rebase -i --continue handles merge strategy and options' '
+test_expect_success 'rebase -i --continue handles merge strategy and options' '
 	rm -fr .git/rebase-* &&
 	git reset --hard commit-new-file-F2-on-topic-branch &&
 	test_commit "commit-new-file-F3-on-topic-branch-for-dash-i" F3 32 &&