Revert "abuild: unset depends for subpackages"

Apparently there are many packages that does soemthing like:

subpackages="$pkgname-foo:_foo"

_foo() {
	depends="$depends something-else"
}

and thus depend on the previous behavior. We need to revert and plan
this better.

This reverts commit 8fbbffd201.

abuild.in

@@ -756,7 +756,6 @@ pre_split() {
 		return 0
 	fi
 	# the subpackages should not inherit those from main package
-	depends=""
 	provides=""
 	install_if=""
 }