chg: make timeout adjustable
Before this patch, chg will give up when it cannot connect to the new server
within 10 seconds. If the host has high load during that time, 10 seconds
is not enough.
This patch makes it adjustable using the CHGTIMEOUT environment variable.
http://example.com/no/anchor, branches: (None, [])
http://example.com/an/anchor, branches: ('foo', [])
http://example.com/no/anchor/branches, branches: (None, ['foo'])
http://example.com/an/anchor/branches, branches: ('bar', ['foo'])
http://example.com/an/anchor/branches-None, branches: ('foo', [])
http://example.com/, branches: (None, [])
http://example.com/, branches: (None, [])
http://example.com/, branches: ('foo', [])