Fix a logging on add_process_layer exceptions.

There were a number of issues with commit 3df5e995 that was applied in
haste (notably, that exceptions wasn't imported in several cases, which
would break the code if it were ever run).

We now give debugging output when a process can't be constructed and
provide as much available information as possible.

Two unused lines were also removed from verinfo.

volatility/framework/plugins/windows/strings.py

@@ -6,7 +6,7 @@ import logging
 import re
 from typing import Dict, Generator, List, Set, Tuple
 
-from volatility.framework import interfaces, renderers
+from volatility.framework import interfaces, renderers, exceptions
 from volatility.framework.configuration import requirements
 from volatility.framework.layers import intel, resources, linear
 from volatility.framework.renderers import format_hints
@@ -95,9 +95,13 @@ class Strings(interfaces.plugins.PluginInterface):
 
             for process in pslist.PsList.list_processes(self.context, self.config['primary'],
                                                         self.config['nt_symbols']):
+                proc_id = "Unknown"
                 try:
+                    proc_id = process.UniqueProcessId
                     proc_layer_name = process.add_process_layer()
-                except exceptions.InvalidAddressException:
+                except exceptions.InvalidAddressException as excp:
+                    vollog.debug("Process {}: invalid address {} in layer {}".format(
+                        proc_id, excp.invalid_address, excp.layer_name))
                     continue
 
                 proc_layer = self.context.layers[proc_layer_name]