Log lease_key when can't obtain it

Currently we log only class name, key usually contains class name
and some IDs which could help identify the problem

app/services/concerns/exclusive_lease_guard.rb

@@ -21,7 +21,7 @@ module ExclusiveLeaseGuard
     lease = exclusive_lease.try_obtain
 
     unless lease
-      log_error("Cannot obtain an exclusive lease for #{self.class.name}. There must be another instance already in execution.")
+      log_error("Cannot obtain an exclusive lease for #{lease_key}. There must be another instance already in execution.")
       return
     end
 

spec/services/concerns/exclusive_lease_guard_spec.rb

@@ -51,7 +51,7 @@ RSpec.describe ExclusiveLeaseGuard, :clean_gitlab_redis_shared_state do
 
       it 'does not call internal_method but logs error', :aggregate_failures do
         expect(subject).not_to receive(:internal_method)
-        expect(Gitlab::AppLogger).to receive(:error).with("Cannot obtain an exclusive lease for #{subject.class.name}. There must be another instance already in execution.")
+        expect(Gitlab::AppLogger).to receive(:error).with("Cannot obtain an exclusive lease for #{subject.lease_key}. There must be another instance already in execution.")
 
         subject.call
       end

spec/services/projects/git_deduplication_service_spec.rb

@@ -139,7 +139,7 @@ RSpec.describe Projects::GitDeduplicationService do
         end
 
         it 'fails when a lease is already out' do
-          expect(service).to receive(:log_error).with("Cannot obtain an exclusive lease for #{service.class.name}. There must be another instance already in execution.")
+          expect(service).to receive(:log_error).with("Cannot obtain an exclusive lease for #{lease_key}. There must be another instance already in execution.")
 
           service.execute
         end

spec/workers/repository_remove_remote_worker_spec.rb

@@ -32,7 +32,7 @@ RSpec.describe RepositoryRemoveRemoteWorker do
 
         expect(subject)
           .to receive(:log_error)
-          .with("Cannot obtain an exclusive lease for #{subject.class.name}. There must be another instance already in execution.")
+          .with("Cannot obtain an exclusive lease for #{lease_key}. There must be another instance already in execution.")
 
         subject.perform(project.id, remote_name)
       end