bundle2: pull bookmark the old way if no bundle2 listkeys support (issue4701) All known server implementations have listkeys support with bundle2, but people in the process of implementing new servers may not. Let's be nice with them.

tests: simplify printenv calls Make printenv executable so that we don't need python, TESTDIR, or quoting.

tests: make printenv executable

tests: simplify calls to dummyssh dummyssh is marked executable and is in the path, no need for python, TESTDIR, or quotes.

tests: remove duplicate inline dummyssh in test-wireproto.t

tests: drop DAEMON_PIDS from killdaemons calls

tests: make killdaemons.py use DAEMON_PIDS by default