pre-push.sample: remove unnecessary and misleading IFS=' '

The sample hook explicitly sets IFS to SP and nothing else so that the "read" used in the per-ref while loop that iterates over "<localref> SP <localsha1> SP <remoteref> SP <remotesha>" records, where we know refs and sha1s will not have SPs, would split them correctly. While this is not wrong per-se, it is not necessary; because we know these fields do not contain HT or LF, either, we can simply leave IFS the default. This will also prevent those who cut and paste from this sample from getting bitten when they write things in the per-ref loop that need splitting with the default $IFS (e.g. use $(git rev-list ...) to produce one-record-per-line output). Signed-off-by: Jim Hill <gjthill@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>