Allow go-leak linter to fail CI (#5316)

## Which problem is this PR solving?
- Part of #5006
- We have only two packages remaining without goroutine leak checks,
both integration tests, which are being worked on
- Meanwhile new code / packages do not benefit from enforcement of
goleak checks because the linter does not fail CI

## Description of the changes
- Add the two remaining packages into exclusion list and force a failure
of the CI if anything else is missing goleak checks

## How was this change tested?
Successful exit:
```shell
$ make goleak
Verifying that all packages with tests have goleak in their TestMain
🔴 Error(check-goleak): no goleak check in package ./cmd/jaeger/internal/integration/
	this package is temporarily allowed and will not cause linter failure
🔴 Error(check-goleak): no goleak check in package ./plugin/storage/integration/
	this package is temporarily allowed and will not cause linter failure
🐞 Warning(check-goleak): no goleak check in 2 package(s).
	See https://github.com/jaegertracing/jaeger/pull/5010/files
	for examples of adding the checks.
```

Unsuccessful exit (forced by removing one of the existing checks):
```shell
$ make goleak
Verifying that all packages with tests have goleak in their TestMain
🔴 Error(check-goleak): no goleak check in package ./cmd/jaeger/internal/integration/
	this package is temporarily allowed and will not cause linter failure
🔴 Error(check-goleak): no goleak check in package ./internal/tracegen/
🔴 Error(check-goleak): no goleak check in package ./plugin/storage/integration/
	this package is temporarily allowed and will not cause linter failure
⛔ Fatal(check-goleak): no goleak check in 3 package(s), 1 of which not allowed.
	See https://github.com/jaegertracing/jaeger/pull/5010/files
	for examples of adding the checks.
make: *** [goleak] Error 1
```

Signed-off-by: Yuri Shkuro <github@ysh.us>

scripts/check-goleak-files.sh

@@ -3,6 +3,7 @@
 set -euo pipefail
 
 bad_pkgs=0
+failed_pkgs=0
 
 # shellcheck disable=SC2048
 for dir in $*; do
@@ -12,23 +13,35 @@ for dir in $*; do
   testFiles=$(find "${dir}" -maxdepth 1 -name '*_test.go')
   if [[ -z "$testFiles" ]]; then
     continue
-  fi 
+  fi
   good=0
   for test in ${testFiles}; do
-    if grep -q "TestMain" "${test}" | grep -q "testutils.VerifyGoLeaks" "${test}"; then
+    if grep -q "TestMain" "${test}" && grep -q "testutils.VerifyGoLeaks" "${test}"; then
       good=1
       break
     fi
   done
   if ((good == 0)); then
     echo "🔴 Error(check-goleak): no goleak check in package ${dir}"
     ((bad_pkgs+=1))
+    if [[ "${dir}" == "./cmd/jaeger/internal/integration/" || "${dir}" == "./plugin/storage/integration/" ]]; then
+      echo "	this package is temporarily allowed and will not cause linter failure"
+    else
+      ((failed_pkgs+=1))
+    fi
   fi
 done
 
-if ((bad_pkgs > 0)); then
-  echo "Error(check-goleak): no goleak check in ${bad_pkgs} package(s)."
-  echo "See https://github.com/jaegertracing/jaeger/pull/5010/files for example of adding the checks."
-  echo "In the future this will be a fatal error in the CI."
-  exit 0 # TODO change to 1 in the future
+function help() {
+  echo "	See https://github.com/jaegertracing/jaeger/pull/5010/files"
+  echo "	for examples of adding the checks."
+}
+
+if ((failed_pkgs > 0)); then
+  echo "⛔ Fatal(check-goleak): no goleak check in ${bad_pkgs} package(s), ${failed_pkgs} of which not allowed."
+  help
+  exit 1
+elif ((bad_pkgs > 0)); then
+  echo "🐞 Warning(check-goleak): no goleak check in ${bad_pkgs} package(s)."
+  help
 fi