Record if JournalLock.obtain_lock() succeeded, use in release_lock()

In the scenario of the default Journals location not even existing the
user needs might update it to a network mount.  When they do so we
attempt, and fail, to unlock the old location, despite it not being
locked.

So now we have this boolean so we know if we should even attempt
unlocking.

journal_lock.py

@@ -37,6 +37,7 @@ class JournalLock:
         self.journal_dir_lockfile_name: Optional[pathlib.Path] = None
         # We never test truthiness of this, so let it be defined when first assigned.  Avoids type hint issues.
         # self.journal_dir_lockfile: Optional[IO] = None
+        self.locked = False
 
     def obtain_lock(self) -> JournalLockResult:
         """
@@ -91,6 +92,8 @@ class JournalLock:
         self.journal_dir_lockfile.flush()
 
         logger.trace('Done')
+        self.locked = True
+
         return JournalLockResult.LOCKED
 
     def release_lock(self) -> bool:
@@ -99,6 +102,9 @@ class JournalLock:
 
         :return: bool - Success of unlocking operation.
         """
+        if not self.locked:
+            return True  # We weren't locked, and still aren't
+
         unlocked = False
         if platform == 'win32':
             logger.trace('win32, using msvcrt')