Streamline lock client usage

[johscheuer]

Description

This PR changes the lock client interface and not getting a lock will result in an error too. We could create a dedicated error type for this, but I think it's easier to work with the lock client this way instead of having two values which were checked differently.

Based on #2212

Type of change

• Bug fix (non-breaking change which fixes an issue)

Discussion

Testing

Unit tests + CI e2e

Documentation

Follow-up

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux CentOS 7

• Commit ID: 430df35
• Duration 2:58:33
• Result: ❌ FAILED
• Error: Error while executing command: if $fail_test; then exit 1; fi. Reason: exit status 1
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux CentOS 7

• Commit ID: d3536f0
• Duration 3:14:13
• Result: ❌ FAILED
• Error: Error while executing command: if $fail_test; then exit 1; fi. Reason: exit status 1
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux CentOS 7

• Commit ID: d3536f0
• Duration 3:09:22
• Result: ❌ FAILED
• Error: Error while executing command: if $fail_test; then exit 1; fi. Reason: exit status 1
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[johscheuer]

Result of fdb-kubernetes-operator-pr on Linux CentOS 7

• Commit ID: d3536f0
• Duration 3:09:22
• Result: ❌ FAILED
• Error: Error while executing command: if $fail_test; then exit 1; fi. Reason: exit status 1
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

Summarizing 1 Failure:
  [FAIL] Operator Upgrades upgrading a cluster with coordinator Pods [It] Upgrade from 7.1.57 to 7.3.59 [e2e, pr]
  /codebuild/output/src3040123046/src/github.com/FoundationDB/fdb-kubernetes-operator/e2e/test_operator_upgrades_variations/operator_upgrades_variations_test.go:149

Ran 8 of 8 Specs in 5781.054 seconds
FAIL! -- 7 Passed | 1 Failed | 0 Pending | 0 Skipped
--- FAIL: TestOperatorUpgradesVariations (5916.65s)
FAIL
FAIL	github.com/FoundationDB/fdb-kubernetes-operator/e2e/test_operator_upgrades_variations	5916.783s
FAIL

That failure seems unrelated 🤔

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux CentOS 7

• Commit ID: d3536f0
• Duration 2:48:27
• Result: ❌ FAILED
• Error: Error while executing command: if $fail_test; then exit 1; fi. Reason: exit status 1
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[nicmorales9]

lgtm