scripts: unset GREP_OPTIONS in env and feeds (fixes #16924)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

Backport of r41407

git-svn-id: svn://svn.openwrt.org/openwrt/branches/attitude_adjustment@41408 3c298f89-4303-0410-b956-a3cf2f4a3e73
AA: hotplug2: use source hosted by OpenWrt as the original source is down

The SVN server used so far seems to have gone down as of 07/2014, so let's just
use the source tarball mirrored by OpenWrt.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

git-svn-id: svn://svn.openwrt.org/openwrt/branches/attitude_adjustment@41503 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge remote-tracking branch 'upstream/master'