tests (radius-otp): add a check radcli version (atleast 1.2.7), since debian uses version
1.2.6, which does not support Access-Challenge server response.
tests: show debug messages only in VERBOSE mode
tests (radius-otp): replace test for option max_challenge to macro MAX_CHALLENGE
Signed-off-by: Alexey Dotsenko <lex@rwx.su>