db-ctl-base: Fix memory leak of db commands. #1899

Job	Run time
dpdk gcc	8s
linux deb no dpdk	9m 23s
osx clang --disable-ssl	3m 55s
linux gcc --disable-ssl	3m 34s
linux clang --disable-ssl	3m 19s
linux gcc c99	3m 13s
linux clang c99	3m 9s
linux gcc test	9m 43s
linux clang test asan	23m 2s
linux clang test ubsan	13m 48s
linux gcc test --enable-shared	16m 15s
linux clang test --enable-shared	14m 40s
linux gcc test dpdk	10m 35s
linux clang test dpdk	11m 32s
linux gcc test -ljemalloc	13m 21s
linux clang test -ljemalloc	13m 24s
linux gcc --enable-afxdp	3m 23s
linux clang --enable-afxdp	3m 36s
linux gcc dpdk --enable-shared	5m 41s
linux clang dpdk --enable-shared	5m 11s
linux gcc dpdk-shared	4m 44s
linux clang dpdk-shared	3m 29s
linux gcc dpdk-shared --enable-shared	5m 25s
linux clang dpdk-shared --enable-shared	5m 53s
linux gcc m32 --disable-ssl	3m 10s
	3h 13m 33s

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