fix dynamic flags

[MegaByte875]

What type of PR is this?

• bug
• feature
• enhancement

What problem(s) does this PR solve?

Issue(s) number:

#289

Description:

How do you solve it?

Special notes for your reviewer, ex. impact of this fix, design document, etc:

creating cluster:

nebula-graph.io/last-applied-dynamic-flags: '{"accept_partial_success":"true","session_reclaim_interval_secs":"300","v":"2"}'
nebula-graph.io/last-applied-static-flags: '{"enable_http2_routing":"true","max_job_size":"36","max_sessions_per_ip_per_user":"10000","port":"8080","prioritize_intra_zone_reading":"true","redirect_stdout":"false","stderrthreshold":"0","stream_timeout_ms":"120000","sync_meta_when_use_space":"true"}'

updating config:
set dynamic flag v=2

set flag accept_partial_success to false and set port to 8081
graphd pod restart again

nebula-graph.io/last-applied-dynamic-flags: '{"accept_partial_success":"false","session_reclaim_interval_secs":"300","v":"2"}'
nebula-graph.io/last-applied-static-flags: '{"enable_http2_routing":"true","max_job_size":"36","max_sessions_per_ip_per_user":"10000","port":"8081","prioritize_intra_zone_reading":"true","redirect_stdout":"false","stderrthreshold":"0","stream_timeout_ms":"120000","sync_meta_when_use_space":"true"}'

scale graphd replicas to 2:

[veezhang]

LGTM