chg: exec pager in child process Before this patch, chg uses the old pager behavior (pre 369741ef7253), which executes pager in the main process. The user will see the exit code of the pager, instead of the hg command. Like 369741ef7253, this patch fixes the behavior by executing the pager in the child process, and wait for it at the end of the main process.

tests: move chg pager test to test-pager.t The test is valid for both hg and chg. Since we are adding another chg-related pager test, let's put them together.

util: drop local aliases for md5, sha1, sha256, and sha512 This used to be needed to paper over hashlib not being in all Pythons we support, but that's not a problem anymore, so we can simplify things a little bit.

cleanup: replace uses of util.(md5|sha1|sha256|sha512) with hashlib.\1 All versions of Python we support or hope to support make the hash functions available in the same way under the same name, so we may as well drop the util forwards.

pathencode: use hashlib.sha1 directly instead of indirecting through util

revlog: use hashlib.sha1 directly instead of through util Also remove module-local _sha alias, which was barely used.

store: use hashlib.sha1 directly instead of through util Also remove module-local alias to _sha, since it's not used that much.

similar: delete extra newline at EOF Spotted by my emacs config that cleans up extra whitespace.

scmutil: delete extra newline at EOF Spotted by my emacs config that cleans up extra whitespace.

graphmod: avoid sorting when already sorted This is somewhat redundant now, but allows us to add a toposort that should not be re-sorted either.