new: globals: Add constants to recover destination

DESTINATION_VERIFY_CERTIFICATE = True

# This number might need adjusted depending on the percentage of circuits and

# HTTP requests failures.

# While the scanner can not recover from some/all failing destionations,

# set a big number so that it continues trying.

MAXIMUM_NUMBER_DESTINATION_FAILURES = 100

# Number of attempts to use a destination, that are stored, in order to decide

# whether the destination is functional or not.

NUM_DESTINATION_ATTEMPTS_STORED = 10

# Time to wait before trying again a destination that wasn't functional.

DELTA_SECONDS_RETRY_DESTINATION = 60 * 60 * 3

# Number of consecutive times a destination can fail before considering it

# not functional.

MAX_NUM_DESTINATION_FAILURES = 3

# By which factor to multiply DELTA_SECONDS_RETRY_DESTINATION when the

# destination fail again.

FACTOR_INCREMENT_DESTINATION_RETRY = 2

def fail_hard(*a, **kw):