Better exception handling in knesset plenum parsing and antiword

[alonisser]

1. Fix strange retry mechanism and log only once in session for specific exception
2. Investigate this:

antiword failure with file: /oknesset_data/oknesset/Open-Knesset/data/plenum_protocols/2015_5_4_20_ptm_305541.doc

plenum/management/commands/parse_plenum_protocols_subcommands/download.py in _antiword

def _antiword(filename):
try:
return antiword(filename, logger)
except:
logger.exception(u'antiword failure with file: %s' % filename)
Local variables
simple/management/utils.py in antiword
logger = local_logger
cmd = 'antiword -x db ' + filename + ' > ' + filename + '.awdb.xml'
logger.debug(cmd)
output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
logger.debug(output)
with open(filename + '.awdb.xml', 'r') as f:

[OriHoch]

hasadna/knesset-data#128 handles moving the plenum scraping to knesset-data

after it's done, should re-review this bug and see if it reproduces on the new architecture or not