Build scripting minor patch

The build script provided in contrib was patched to search for meta-redhawk-sdr in the parent folder. This will allow the old and new (meta-redhawk-sdr-manifests, Poky) filesystem styles to work by linking this same script into your ./build folder. The script facilitates bitbaking and then deploying the build as a single image file describing a dual-partition setup. (Results will still vary based on what BSP you've targeted. For example, Xilinx's BSPs still require you to make U-BOOT environment changes to boot from the SD card with a non-volatile root partition.)