examples/some.cf: update example to show testing for an empty list

(cherry picked from commit ca5f6bca623b486bdb404c6532eec183994b8550)
examples/some.cf: update example comments

(cherry picked from commit 3b7d8b8973d36c8e85aea043154a5c2644b0d02a)
examples/readtcp.cf: do not test output

(cherry picked from commit 60f0d443c70cdc4a75cdf276631598284a2a523e)
tests/acceptance/18_examples/ouputs/check_outputs.cf: not a network test anymore

(cherry picked from commit 2864702bd1b12572c3f5f8a192a694741a710139)
examples/some.cf: update example to show testing for an empty list

(cherry picked from commit ca5f6bca623b486bdb404c6532eec183994b8550)

Conflicts:
	examples/some.cf
examples/some.cf: update example comments

(cherry picked from commit 3b7d8b8973d36c8e85aea043154a5c2644b0d02a)
tests/acceptance/testall: mention $PRINTLOG

(cherry picked from commit 409e12a39444d26b3cd8305bd5afb339805423c4)
Redmine#5959: test this.promises in command args

(cherry picked from commit 3c886bc8339bbcf1eb3f016a523284c5a140ca90)
cf-agent/verify_users.c: "user promise kept" should be VERBOSE, not INFO

(cherry picked from commit 916f35e07b760b3fe4e1c222caa685ab663483ae)
Redmine#5957 Install the default agent signal handler for cf-key

(cherry picked from commit ed35e1d2a799bef8e6a793309904d78c43a36bb0)
Merge remote-tracking branch 'upstream/3.6.x' into 3.6.x