Unix tar: do not preserve full pathnames
This is ugly... but it works...
I had this same problem but with multiple folders, I just wanted to flat every files out. You can use the option "transform" to pass a sed expression and... it works as expected.
this is the expression:
's/.*\///g' (delete everything before '/')
This is the final command:
tar --transform 's/.*\///g' -zcvf tarballName.tgz */*/*.info