Issue #107 GVM doesn't work on Cygwin quickfix

this solves problem only in case when unzip comes from oracledb (both I and author of issue struggle with this)

maybe it should be better solution to check if used unzip is that should be ie. for example use

expr match "$(unzip)" ".*Original by Info-ZIP*" 
unzip help contains text "Original by Info-ZIP") 

which tell us if we are gonna use right unzip program - it expr check fails it means that our path is poluted by other incompatible version of unzip program and we should tell the user about...