bugfix: fix wrongly update cpu-quota to 0

[HusterWan]

Signed-off-by: Michael Wan zirenwan@gmail.com

Ⅰ. Describe what this PR did

On kernel, cpu.cfs_quota_us only support:

• -1: not limit container's cpu-quota
• [1000, ∞) : correct values for cpu-quota

So 0 is not a valid value for cpu-quota, we can use 0 to distinct not set from other values in api. In PouchContainer API:

• 0: don't set cpu-quota
• -1: not limit containers'cpu-quota
• [1000, ∞) : correct values for cpu-quota

Ⅱ. Does this pull request fix one issue?

fix: #2538

Ⅲ. Why don't you add test cases (unit test/integration test)? (你真的觉得不需要加测试吗？)

add test case: PouchUpdateSuite.TestUpdateContainerCPUQuota

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

Merging #2684 into master will increase coverage by 0.61%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2684      +/-   ##
==========================================
+ Coverage   66.85%   67.46%   +0.61%     
==========================================
  Files         276      278       +2     
  Lines       17361    17392      +31     
==========================================
+ Hits        11606    11734     +128     
+ Misses       4490     4338     -152     
- Partials     1265     1320      +55

Flag	Coverage Δ
#criv1alpha2_test	39.36% <100%> (?)
#integration_test_0	36.24% <100%> (-0.2%)	⬇️
#integration_test_1	35.18% <0%> (-0.03%)	⬇️
#integration_test_2	?
#integration_test_3	35.13% <0%> (-0.06%)	⬇️
#node_e2e_test	35.11% <0%> (+0.01%)	⬆️
#unittest	27.36% <0%> (ø)	⬆️

Impacted Files	Coverage Δ
daemon/mgr/container.go	58.4% <100%> (-0.64%)	⬇️
storage/volume/modules/tmpfs/tmpfs.go	28.2% <0%> (-47.44%)	⬇️
daemon/events/filter.go	60% <0%> (-40%)	⬇️
apis/server/system_bridge.go	17.2% <0%> (-32.26%)	⬇️
apis/server/utils.go	53.84% <0%> (-21.16%)	⬇️
pkg/utils/mount.go	0% <0%> (-19.24%)	⬇️
daemon/mgr/container_list.go	61.16% <0%> (-17.48%)	⬇️
daemon/mgr/system.go	58.77% <0%> (-16.04%)	⬇️
daemon/events/events.go	68.36% <0%> (-13.27%)	⬇️
pkg/utils/filters/filter.go	65% <0%> (-12.5%)	⬇️
... and 40 more

[wangforthinker]

LGTM

[rudyfly]

LGTM

[zjumoon01]

Is it should be "!=" rather than "=="