recipetool: create: avoid decoding errors with Python 3
We're opening source files with the default encoding (utf-8) but we
can't necessarily be sure that they are UTF-8 clean - for example,
recipetool create ftp://mama.indstate.edu/linux/tree/tree-1.7.0.tgz
prior to this patch resulted in a UnicodeDecodeError. Use the
"surrogateescape" mode to avoid this.
Fixes [YOCTO #9822].
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
