解决exchangis启动重复引擎的问题

[zdfhub]

What is the purpose of the change

fix issues/416 解决exchangis启动重复引擎的问题。

Brief change log

(for example:)

• defines the job server module of Exchangis;
• defines the job launcher module of Exchangis;
• defines the job metrics module of Exchangis.

Verifying this change

(Please pick either of the following options)
This change is a trivial rework / code cleanup without any test coverage.
(or)
This change is already covered by existing tests, such as (please describe tests).
(or)
This change added tests and can be verified as follows:
(example:)

• Added tests for creating and execute the Exchangis jobs and verify the availability of different Exchangis Job, such as sqoop job, datax job.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• Anything that affects deployment: (yes / no / don't know)
• The Core framework, i.e., JobManager, Server.: (yes / no)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)