clamav: create DB directory in post-install (#113649)
clamav: create DB directory in post-install (#113649)

Fixes https://github.com/Homebrew/homebrew-core/issues/113442#issuecomment-1286076558
nandub/homebrew-core,Homebrew/homebrew-core,filcab/homebrew-core,chrisfinazzo/homebrew-core,stgraber/homebrew-core,Homebrew/homebrew-core,adam-moss/homebrew-core,lemzwerg/homebrew-core,nandub/homebrew-core,chrisfinazzo/homebrew-core,stgraber/homebrew-core,makigumo/homebrew-core,lemzwerg/homebrew-core,filcab/homebrew-core,adam-moss/homebrew-core,makigumo/homebrew-core