bin/xbps-rindex/sign.c: fix a double free in error path found by clang-analyzer.
bin/xbps-rindex/sign.c: fix a double free in error path found by clang-analyzer.

stpx/xbps,ebfe/xbps,stpx/xbps,datenwolf/xbps,stpx/xbps,datenwolf/xbps,ebfe/xbps,ebfe/xbps,datenwolf/xbps