This patch changes open_file_read() and open_file_write() to use 
errors='surrogateescape' (with fallback to 'replace' for py2).

This avoids a crash when reading a logfile with special characters that 
are not utf8-encoded (for example a latin1 "ö"), and also avoids crashes 
at several other places we don't know yet ;-)

The patch also changes open_file_read() and open_file_write() to wrapper
functions, and moves the "real" code to the new open_file_anymode() 
function.

Also, I removed the try/except - it's superfluous because it throws the 
exception without any modifications.


Acked-by: Kshitij Gupta <kgupta8592@gmail.com>