Fix const warnings in http-fetch.c and remote-curl.c main() where is
argv declared as const.
The fix should work for all future declarations of main, no matter
whether the second parameter's type is "char**", "const char**", or
"char *[]".
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>