OpenCL format memory leaks

[solardiz]

    #2 0x560cdb2fe3ba in w_block_precomputed /home/user/john/src/opencl_bitlocker_fmt_plug.c:383
    #2 0x560cdb300316 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:133
    #2 0x560cdb300331 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:134
    #2 0x560cdb300345 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:135
    #2 0x560cdb30038a in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:138
    #2 0x560cdb3003a0 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:139
    #2 0x560cdb3003b6 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:140
    #2 0x560cdb3003cc in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:141
    #2 0x560cdb3003e2 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:142
    #2 0x560cdb3003f8 in create_clobj /home/user/john/src/opencl_bitlocker_fmt_plug.c:143
    #2 0x560cdb344098 in create_clobj /home/user/john/src/opencl_diskcryptor_aes_fmt_plug.c:134
    #2 0x560cdb349100 in create_clobj /home/user/john/src/opencl_diskcryptor_fmt_plug.c:132
    #2 0x560cdb349154 in create_clobj /home/user/john/src/opencl_diskcryptor_fmt_plug.c:137
    #2 0x560cdb35765e in create_clobj /home/user/john/src/opencl_electrum_modern_fmt_plug.c:156
    #2 0x560cdb36d2a5 in create_clobj /home/user/john/src/opencl_ethereum_presale_fmt_plug.c:113
    #2 0x560cdb51b9d6 in create_clobj /home/user/john/src/opencl_solarwinds_fmt_plug.c:124

The one in BitLocker is pretty bad in that it can accumulate during cracking (but I think only when there's more than one salt). The rest are mostly cosmetic, but they increase memory usage of multi-format --test.