[PATCH 09 of 10] tests: mark test-context.py write as binary

[timeless]

# HG changeset patch
# User timeless <timeless at mozdev.org>
# Date 1461181981 0
#      Wed Apr 20 19:53:01 2016 +0000
# Node ID 0fb40274d36c42e8fe4eb70166fb5d85496a94f3
# Parent  25f8295b734c14c16273663d7a16066cb0abaa88
# Available At bb://timeless/mercurial-crew
#              hg pull bb://timeless/mercurial-crew -r 0fb40274d36c
tests: mark test-context.py write as binary

diff -r 25f8295b734c -r 0fb40274d36c tests/test-context.py
--- a/tests/test-context.py	Wed Apr 20 20:05:31 2016 +0000
+++ b/tests/test-context.py	Wed Apr 20 19:53:01 2016 +0000
@@ -14,7 +14,7 @@
 
 # create 'foo' with fixed time stamp
 f = open('foo', 'wb')
-f.write('foo\n')
+f.write(b'foo\n')
 f.close()
 os.utime('foo', (1000, 1000))