Failed to prepare a jvm experiment if the process creator‘s name is too long

[Vascal]

Issue Description

Type: bug report

Describe what happened (or what feature you want)

When preparing a jvm experiment, if the java process creator's name is too long, then the jvm-sandbox injection failed and return:
{"code":604,"success":false,"error":"sudo: unknown user: testlongus+\nsudo: unable to initialize policy plugin\n exit status 1","result":"8590462124aae6f6"}"

such as,

Describe what you expected to happen

prepare successful

How to reproduce it (as minimally and precisely as possible)

1. Start a java process with a long-name user.
   2.Use blade to prepare with this java process.

Tell us your environment

Cent OS 7.x

Anything else we need to know?