clamav: fix invalid zlib version error

clamav: fix invalid zlib version error

ClamAV's configure script uses grep to check for bugy zlib version
1.2.1. Since current OpenWrt zlib version is 1.2.11 this check passes
and build fails. This patch will disable this unneeded check and make
sure we are looking for zlib on the right location.

clamdtop was beeing built without it's ncurses dependency. Build system
would link it to the host's ncurses making the program fail at run time.
This patch will disable building of optional clamdtop, otherwise we need
to add ncurses as a dependency and fix the search path.

Increase PKG_RELEASE to reflect changes.

Signed-off-by: Marko Ratkaj <marko.ratkaj@sartura.hr>