[python][cleanup][lock] Remove fallback Lock implementation since portalocker...

[python][cleanup][lock] Remove fallback Lock implementation since portalocker is a required dependency

python/dune/common/locking.py

-try:
-    from portalocker import Lock as _Lock
-    from portalocker.constants import LOCK_EX, LOCK_SH
-    class Lock(_Lock):
-        def __init__(self, path, flags, *args, **kwargs):
-            _Lock.__init__(self,path,*args,flags=flags,timeout=None,**kwargs)
-except ModuleNotFoundError:
-    import os
-    import fcntl
-    from fcntl import LOCK_EX, LOCK_SH
-    # file locking from fcntl
-    def lock_file(f, cmd=fcntl.LOCK_EX):
-        fcntl.flock(f, cmd)
-        return f
-    def unlock_file(f):
-        fcntl.flock(f, fcntl.LOCK_UN)
-        return f
+from portalocker import Lock as _Lock
+from portalocker.constants import LOCK_EX, LOCK_SH
 
-    # This file opener *must* be used in a "with" block.
-    class Lock:
-        # Open the file with arguments provided by user. Then acquire
-        # a lock on that file object (WARNING: Advisory locking).
-        def __init__(self, path, flags, *args, **kwargs):
-            # Open the file and acquire a lock on the file before operating
-            self.file = open(path, mode='w+', *args, **kwargs)
-            # Lock the opened file
-            self.file = lock_file(self.file, flags) # flags are either LOCK_EX or LOCK_SH
-
-        # Return the opened file object (knowing a lock has been obtained).
-        def __enter__(self, *args, **kwargs): return self.file
-
-        # Unlock the file and close the file object.
-        def __exit__(self, exc_type=None, exc_value=None, traceback=None):
-            # Flush to make sure all buffered contents are written to file.
-            self.file.flush()
-            os.fsync(self.file.fileno())
-            # Release the lock on the file.
-            self.file = unlock_file(self.file)
-            self.file.close()
-            # Handle exceptions that may have come up during execution, by
-            # default any exceptions are raised to the user.
-            return exc_type == None
+class Lock(_Lock):
+    """A lock to prevent data races in situations with multiple processes"""
+    def __init__(self, path, flags, *args, **kwargs):
+        _Lock.__init__(self, path, *args, flags=flags, timeout=None, **kwargs)