Remove pdb support

[hzxuzhonghu]

Actually the pdb feature can not work well. Remove it.

Fixes: #628

@jianxingzhe Can you test with this pr?

[TravisBuddy]

Hey @hzxuzhonghu,
Your changes look good to me!

View build log

TravisBuddy Request Identifier: f6bee5b0-2ae3-11ea-b3af-3392aa6c8569

[jianxingzhe]

Actually the pdb feature can not work well. Remove it.

Fixes: #628

@jianxingzhe Can you test with this pr?

the volcano scheduler start successfully in our cluster with this pr. thank you very much.

kubectl get pod -n volcano-system
NAME                                   READY   STATUS      RESTARTS   AGE
volcano-admission-fd4b955cf-2dxkw      1/1     Running     0          29h
volcano-admission-init-fngph           0/1     Completed   0          29h
volcano-controllers-57864457d4-tzxqm   1/1     Running     0          29h
volcano-scheduler-675c5ff757-mf657     1/1     Running     0          6m51s

[k82cn]

/lgtm
/approve

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hzxuzhonghu, k82cn

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