Really make the LF after reset in fast-import optional

cmd_from() ends with a call to read_next_command(), which is needed
when using cmd_from() from commands where from is not the last element.

With reset, however, "from" is the last command, after which the flow
returns to the main loop, which calls read_next_command() again.

Because of this, always set unread_command_buf in cmd_reset_branch(),
even if cmd_from() was successful.

Add a test case for this in t9300-fast-import.sh.

Signed-off-by: Adeodato Simó <dato@net.com.org.es>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fast-import.c

@@ -2261,7 +2261,8 @@ static void cmd_reset_branch(void)
 	else
 		b = new_branch(sp);
 	read_next_command();
-	if (!cmd_from(b) && command_buf.len > 0)
+	cmd_from(b);
+	if (command_buf.len > 0)
 		unread_command_buf = 1;
 }
 

t/t9300-fast-import.sh

@@ -869,6 +869,8 @@ zcommits
 COMMIT
 reset refs/tags/O3-2nd
 from :5
+reset refs/tags/O3-3rd
+from :5
 INPUT_END
 
 cat >expect <<INPUT_END