Ignore cache files when comparing synced parts

Prior to the Related-Change no suffixes were written to hashes.invalid
until after initial suffix hashing created hashes.pkl - and in our probe
test the only updates to the partition occurred before replication.

Before the related change with sync_method = rsync it was possible when
starting from a clean slate to write data, and replicate from a handoff
partition without generating a hashes.invalid file in any primary.

After the Related-Change it was no longer possible to write data without
generating a hashes.invalid file; however with sync_method = rsync the
replicator could still replicate data into a partition that never
received an update directly and therefore no hashes.invalid.

When using sync_method = ssync replication updates the hashes.invalid
like any normal update to the partition and therefore all partitions
always have a hashes.invalid.

This change opts to ignores these implementation details in the probe
tests when comparing the files between synced partitions by
black-listing these known cache files and only validates that the disk
file's on disk files are in sync.

Related-Change-Id: I2b48238d9d684e831d9777a7b18f91a3cef57cd1

Change-Id: Ia9c50d7bc1a74a17c608a3c3cfb8f93196fb709d
Closes-Bug: #1663021

test/probe/test_replication_servers_working.py

@@ -26,6 +26,8 @@ from swift.obj.diskfile import get_data_dir
 from test.probe.common import ReplProbeTest
 from swift.common.utils import readconf
 
+EXCLUDE_FILES = ['hashes.pkl', 'hashes.invalid', '.lock']
+
 
 def collect_info(path_list):
     """
@@ -41,6 +43,7 @@ def collect_info(path_list):
         temp_files_list = []
         temp_dir_list = []
         for root, dirs, files in os.walk(path):
+            files = [f for f in files if f not in EXCLUDE_FILES]
             temp_files_list += files
             temp_dir_list += dirs
         files_list.append(temp_files_list)