subrepo: invoke "_sanitize()" also after "git merge --ff" Before this patch, sanitizing ".hg/hgrc" in git subrepo doesn't work, when the working directory is updated by "git merge --ff". "_sanitize()" is not invoked after checking target revision out into the working directory in this case, even though it is invoked indirectly via "checkout" (or "rawcheckout") in other cases. This patch invokes "_sanitize()" explicitly also after "git merge --ff" execution.

subrepo: make "_sanitize()" work "_sanitize()" was introduced by 224e96078708 on "stable" branch, but it has done nothing for sanitizing since 224e96078708. "_sanitize()" assumes "Visitor" design pattern: "os.walk()" should invoke specified function ("v" in this case) for each directory elements under specified path but "os.walk()" assumes "Iterator" design pattern: callers of it should drive loop to scan each directory elements under specified path by themselves with the returned generator object Because of this mismatching, "_sanitize()" just discards the generator object returned by "os.walk()" and does nothing for sanitizing. This patch makes "_sanitize()" work. This patch also changes the format of warning message to show each unlinked files, for multiple appearances of "potentially hostile .hg/hgrc".