bookmarks: prevent divergent bookmark from being updated unexpectedly Before this patch, "@99" suffixed bookmark may be updated unexpectedly by the bookmark value on the remote side at "hg pull", if all of "@1" to "@99" suffixed bookmarks exist in the local repository, because variable "n" still refers "@99" suffixed bookmark after the loop to examine "@num" suffixes, even though it already exists in the local repository. This patch prevents divergent bookmark from being updated unexpectedly, and shows warning message in such situation. This patch uses original python script "seq.py" instead of "seq" command to create sequence numbers in the test, because "seq" command may not be available: it isn't defined in recent POSIX specification (POSIX.1-2001 2013 Edition or XPG7)