transport: drop "int cmp = cmp" hack

transport: drop "int cmp = cmp" hack

According to 47ec794, this initialization is meant to
squelch an erroneous uninitialized variable warning from gcc
4.0.1.  That version is quite old at this point, and gcc 4.1
and up handle it fine, with one exception. There seems to be
a regression in gcc 4.6.3, which produces the warning;
however, gcc versions 4.4.7 and 4.7.2 do not.

Signed-off-by: Jeff King <redacted>
Reviewed-by: Jonathan Nieder <redacted>
Signed-off-by: Junio C Hamano <redacted>