`vs migrate` has an invalid filter

[allmightyspiff]

Filtering off pendingMigrationFlag doesn't look to actually work.

$> slcli call-api SoftLayer_Account getVirtualGuests --mask="mask[id,hostname,pendingMigrationFlag]" --json-filter='{"virtualGuests":{"pendingMigrationFlag":{"operation":0}}}'
┌──────────────────┬───────────┬──────────────────────┐
│     hostname     │    id     │ pendingMigrationFlag │
├──────────────────┼───────────┼──────────────────────┤
│       adns       │ 100250634 │        False         │
│ cgallo-bnpp-test │ 139920549 │        False         │
│       cp4d       │ 133871998 │        False         │
│    easerverh     │ 132364928 │        False         │
│     haproxy      │ 133986540 │        False         │
│     instana      │ 132690142 │         True         │
│      pxe-1       │ 133926476 │        False         │
│     reserved     │ 102396266 │        False         │
└──────────────────┴───────────┴──────────────────────┘
 slcli call-api SoftLayer_Account getVirtualGuests --mask="mask[id,hostname,pendingMigrationFlag]" --json-filter='{"virtualGuests":{"pendingMigrationFlag":{"operation":1}}}'
[]

$> slcli -v vs migrate
Calling: SoftLayer_Account::getVirtualGuests(id=None, mask='mask[ id, hostname, domain, datacenter, pendingMigrationFlag, powerState, primaryIpAddress,primaryBackendIpAddress, dedicatedHost ]', filter='{'virtualGuests': {'pendingMigrationFlag': {'operation': 1}}}', args=(), limit=100, offset=0)
No guests require migration at this time