main/tar: do not symlink tar under /usr

busybox's tar is installed only under /bin. This file being duplicated
across the /usr hierarchy breaks the /usr merge script. There's the
unlikely chance that something has tar hard-coded with the /usr path,
but there seems to be nothing in aports or mkinitfs, and that would
still be broken with tar from busybox

main/tar/APKBUILD

 # Maintainer: Carlo Landmeter <clandmeter@alpinelinux.org>
 pkgname=tar
 pkgver=1.35
-pkgrel=2
+pkgrel=3
 pkgdesc="Utility used to store, backup, and transport files"
 url="https://www.gnu.org/software/tar/"
 arch="all"
@@ -54,7 +54,6 @@ package() {
 
 	mkdir "$pkgdir"/bin
 	mv "$pkgdir"/usr/bin/tar "$pkgdir"/bin/
-	ln -s /bin/tar "$pkgdir"/usr/bin/tar
 }
 
 sha512sums="