jenkins.sh: change qemu-img default location to $HOME/qemu-img instead of /opt/qemu-img
jenkins.sh: change qemu-img default location to $HOME/qemu-img instead of /opt/qemu-img

Change-Id: I56f314d78c0ca968b1fef9a91ecd540a7cc8fa86

ttsou/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx,ttsou/osmo-trx,ttsou/osmo-trx,ttsou/osmo-trx,osmocom/osmo-trx