migrated secop_psi drivers to new syntax

- includes all changes up to 'fix inheritance order' from git_mlz
  6a32ecf342

Change-Id: Ie3ceee3dbd0a9284b47b1d5b5dbe262eebe8f283

secop/errors.py

@@ -22,7 +22,6 @@
 """Define (internal) SECoP Errors"""
 
 
-
 class SECoPError(RuntimeError):
 
     def __init__(self, *args, **kwds):
@@ -138,12 +137,6 @@ def secop_error(exception):
     return InternalError(repr(exception))
 
 
-def fmt_error(exception):
-    if isinstance(exception, SECoPError):
-        return str(exception)
-    return repr(exception)
-
-
 EXCEPTIONS = dict(
     NoSuchModule=NoSuchModuleError,
     NoSuchParameter=NoSuchParameterError,