verify_*.py: Ignore UTF-8 decoding errors

Some of our source files are inherited from other sources, particularly
for microcontroller firmware projects.  We cannot assume they're all
clean UTF-8.  Let's ignore any decoder errors when verifying log
statements and value_string arrays.

Closes: OS#4334
Change-Id: I1e19f4bc6bee46481c6ea743e8334bd4485909be

scripts/verify_log_statements.py

@@ -66,7 +66,7 @@ def check_file(f):
   try:
     errors_found = []
 
-    file_content = codecs.open(f, "r", "utf-8").read()
+    file_content = codecs.open(f, "r", "utf-8", errors='ignore').read()
 
     for log in log_statement_re.finditer(file_content):
       quoted = log.group(2)

scripts/verify_value_string_arrays_are_terminated.py

@@ -27,7 +27,7 @@ def check_file(f):
   global errors_found
   if not (f.endswith('.h') or f.endswith('.c') or f.endswith('.cpp')):
     return
-  arrays = value_string_array_re.findall(codecs.open(f, "r", "utf-8").read())
+  arrays = value_string_array_re.findall(codecs.open(f, "r", "utf-8", errors='ignore').read())
   for array_def, name in arrays:
     if not terminator_re.search(array_def):
       print('ERROR: file contains unterminated value_string %r: %r'