contrib: build-osmocom-bb: Download and install osmocom-bb fw from OBS

As it's quite complex to build osmocom firmware nowadays (a specific old
release of gcc and binutils are required to build it), instead download
the already built binaries from OBS.

Change-Id: I2571268d91e2430a270e51438608e7dbd121e76d
diff --git a/contrib/jenkins-build-osmocom-bb.sh b/contrib/jenkins-build-osmocom-bb.sh
index f54518a..d5eec1e 100755
--- a/contrib/jenkins-build-osmocom-bb.sh
+++ b/contrib/jenkins-build-osmocom-bb.sh
@@ -5,6 +5,8 @@
 name="osmocom-bb"
 . "$(dirname "$0")/jenkins-build-common.sh"
 
+FW_RPM_URL="http://download.opensuse.org/repositories/home:/mnhauke:/osmocom:/nightly/SLE_15/x86_64/"
+
 build_repo libosmocore --disable-doxygen
 
 have_repo osmocom-bb
@@ -20,5 +22,12 @@
 set +x; echo; echo; set -x
 make install
 
+mkdir -p "$prefix"
+cd "$prefix"
+FW_RPM="$(wget -q -O - "$FW_RPM_URL" | grep -o 'osmocom-bb-firmware.*rpm' | sed 's#\"#\n#g' | head -1)"
+echo "Downloading RPM package $FW_RPM"
+wget -q "$FW_RPM_URL/$FW_RPM" -O osmocom-bb-firmware.rpm
+rpm2cpio osmocom-bb-firmware.rpm  | cpio -idmv
+rm osmocom-bb-firmware.rpm
 
 create_bin_tgz "" "osmocon"