fix missing import (only affected non-linux systems)

spectrumctl/spectrum/spectrum.py

@@ -292,6 +292,7 @@ def status( self, pid=None ):
 				return 0 # "running."
 			except OSError, err:
 			# except OSError as err: #python3
+				import errno
 				if err.errno == errno.ESRCH:
 					return 1 # "not running but pid file exists."
 				else: