libbladeRF: Added error code return after assertion (CID 1213847)

Ensure this function can't proceed if release assertions become
disabled, and to appease static analysis tools.
libbladeRF: Fixed potential memory leak in cases with bad args  (CID 1213846)
bladeRF-cli: Fixed leak of expanded path name (CID 1206512)
bladeRF-cli: Fixed leak in case where image alloc fails (CID1206511)
bladeRF-cli: Fixed leak in TX file conversion faliure (CID 1206510)
libbladeRF: Fixed leak in FPGA flashing failure case (CID 1104234)