influx_inspect: export does not escape field keys

[mark-rushakoff]

When running influx_inspect export on data with a measurement containing a space, or probably other special characters, the generated line protocol is invalid. For example, when exporting the NOAA data, which has a field named level description, the output does not escape:

Current behavior:

h2o_feet,location=coyote_creek level description="below 3 feet" 1439910360000000000

Expected behavior:

h2o_feet,location=coyote_creek level\ description="below 3 feet" 1439910360000000000