tests/test-filelog.py.out

convert: when converting from Perforce use original local encoding by default

On Windows Perforce command line client uses default system locale to encode
output. Using 'latin_1' causes locale-specific characters to be replaced with
question marks. With this patch we will use default locale by default whilst
allowing to specify it explicity with 'convert.p4.encoding' config option.

This is a potentially breaking change for any scripts relying on output treated
as in 'latin_1' encoding.

Also because hgext.convert.convcmd overwrites detected default system locale
with UTF-8 we had to introduce an import cycle in hgext.convert.p4 to retrieve
originally detected encoding from hgext.convert.convcmd.

ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.