ping() does not deal with truncated responses

[bewing]

Some destinations truncate payload in echo messages

napalm-eos version

(Paste verbatim output from pip freeze | grep napalm-eos between quotes below)

napalm-base==0.23.2
napalm-eos==0.5.6

eOS version

(Paste verbatim output from show version | json between quotes below)

{u'architecture': u'i386',
  u'bootupTimestamp': 1488060828.73,
  u'hardwareRevision': u'01.03',
  u'internalBuildId': u'8f820a40-8597-41b7-8871-2ba47ffd0aad',
  u'internalVersion': u'4.16.9M-3799680.4169M',
  u'isIntlVersion': False,
  u'memFree': 188640,
  u'memTotal': 3978076,
  u'modelName': u'DCS-7150S-64-CL-R',
  u'version': u'4.16.9M'}

Steps to Reproduce the Issue

import napalm_eos
d = device('veos1', 'admin', 'admin')
d.open()
d.device.run_commands(["ping 8.8.8.8"])[0]
d.ping("8.8.8.8")

Error Traceback

(Paste the complete traceback of the exception between quotes below)

{u'messages': [u'PING 8.8.8.8 (8.8.8.8) 72(100) bytes of data.\n72 bytes from 8.8.8.8: icmp_req=1 ttl=41 (truncated)\n72 bytes from 8.8.8.8: icmp_req=2 ttl=41 (truncated)\n72 bytes from 8.8.8.8: icmp_req=3 ttl=41 (truncated)\n72 bytes from 8.8.8.8: icmp_req=4 ttl=41 (truncated)\n72 bytes from 8.8.8.8: icmp_req=5 ttl=41 (truncated)\n\n--- 8.8.8.8 ping statistics ---\n5 packets transmitted, 5 received, 0% packet loss, time 102ms\nrtt min/avg/max/mdev = 24.904/25.067/25.643/0.305 ms, ipg/ewma 25.507/25.345 ms\n']}
napalm-eos/napalm_eos/eos.pyc in ping(self, destination, source, ttl, timeout, size, count, vrf)
   1685                         m = fields[6][5:]
   1686                         results_array.append({'ip_address': py23_compat.text_type(fields[3]),
-> 1687                                               'rtt': float(m)})
   1688                 elif 'packets transmitted' in line:
   1689                     ping_dict['success']['probes_sent'] = int(fields[0])

ValueError: could not convert string to float: cated)

FYI, Google is appearing to truncate ICMP responses > 64 bytes:

ping -s 80 -c 4 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 80(108) bytes of data.
72 bytes from 8.8.8.8: icmp_seq=1 ttl=44 (truncated)
72 bytes from 8.8.8.8: icmp_seq=2 ttl=44 (truncated)
72 bytes from 8.8.8.8: icmp_seq=3 ttl=44 (truncated)
72 bytes from 8.8.8.8: icmp_seq=4 ttl=44 (truncated)

--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 10.462/10.508/10.530/0.027 ms

ping -s 64 -c 4 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 64(92) bytes of data.
72 bytes from 8.8.8.8: icmp_seq=1 ttl=44 time=10.5 ms
72 bytes from 8.8.8.8: icmp_seq=2 ttl=44 time=10.5 ms
72 bytes from 8.8.8.8: icmp_seq=3 ttl=44 time=10.5 ms
72 bytes from 8.8.8.8: icmp_seq=4 ttl=44 time=10.5 ms

--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 10.505/10.516/10.540/0.126 ms