Added exception to handle json parsing error when ordering

[acamacho82]

try/catch was added to handle json decode errors in the --extras value, it should fix #1107

slcli order place and slcli order place-quote

output python 2.7:
There was an error when parsing the --extras value: No JSON object could be decoded

output python 3:
There was an error when parsing the --extras value: Expecting value: line 1 column 28 (char 27)

[coveralls]

Coverage increased (+0.03%) to 91.701% when pulling b00f68b on acamacho82:1107 into ae19bc2 on softlayer:master.