improvement: GFD pod will be reaped after it has succeeded

[rajatchopra]

Two tasks:

1. Delete an existing GFD pod when device plugin starts/restarts
2. Delete the GFD pod after if it has succeeded

[coveralls]

Pull Request Test Coverage Report for Build 21961788604

Details

• 0 of 50 (0.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-1.6%) to 26.784%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/device_plugin/gfd.go	0	50	0.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/device_plugin/gfd.go	1	2.48%

Totals
Change from base Build 21924059146:	-1.6%
Covered Lines:	229
Relevant Lines:	855

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💛 - Coveralls