fix(OutputWatcher): use formatted string in log message

Sometimes line for output  could contain '%s' or '0.0%' and this break
OutputWatcher log function with error:
```
18:42:47      msg = msg % self.args
18:42:47  ValueError: incomplete format

File "/home/ubuntu/scylla-cluster-tests/sdcm/remote/libssh2_client/__init__.py", line 449, in _process_output
      watcher.submit_line(data)
File "/home/ubuntu/scylla-cluster-tests/sdcm/remote/base.py", line 231, in submit_line
      self.log.debug("<%s>: " + line.rstrip('\n'), self.hostname)
Message: '<%s>: Percent Repaired       : 0.0%'
Arguments: ('10.4.0.228',)
```

Job: https://jenkins.scylladb.com/job/scylla-staging/job/abykov/job/longevity-twcs-4h-staging-test/20/execution/node/164/

Change format for log message info

self.log.debug("%s - %s', self.hostname, line)

sdcm/remote/base.py

@@ -222,13 +222,13 @@ def submit(self, stream: str) -> list:
 
         while '\n' in stream_buffer:
             out_buf, rest_buf = stream_buffer.split('\n', 1)
-            self.log.debug("<%s>: " + out_buf, self.hostname)
+            self.log.debug("<%s>: %s", self.hostname, out_buf)
             stream_buffer = rest_buf
         self.len = len(stream) - len(stream_buffer)
         return []
 
     def submit_line(self, line: str):
-        self.log.debug("<%s>: " + line.rstrip('\n'), self.hostname)
+        self.log.debug("<%s>: %s", self.hostname, line.rstrip('\n'))
 
 
 class LogWriteWatcher(StreamWatcher):  # pylint: disable=too-few-public-methods