main/tree: fix install destination

tree was installed to /usr instead of /usr/bin.

main/tree/APKBUILD

 # Maintainer: Leonardo Arena <rnalrd@alpinelinux.org>
 pkgname=tree
 pkgver=2.0.1
-pkgrel=0
+pkgrel=1
 pkgdesc="A recursive directory indented listing of files"
 url="http://mama.indstate.edu/users/ice/tree/"
 arch="all"
 license="GPL-2.0-or-later"
-depends=""
-depends_dev=""
 makedepends="$depends_dev"
-install=""
 options="!check"
 subpackages="$pkgname-doc"
-source="http://mama.indstate.edu/users/ice/tree/src/$pkgname-$pkgver.tgz
+source="http://mama.indstate.edu/users/ice/tree/src/tree-$pkgver.tgz
 	0001-remove-03-cflag.patch
 	"
 
@@ -21,7 +18,7 @@ build() {
 }
 
 package() {
-	make DESTDIR="$pkgdir/usr" MANDIR="${pkgdir}/usr/share/man" install
+	make PREFIX="$pkgdir/usr" MANDIR="$pkgdir/usr/share/man" install
 }
 
 sha512sums="