Change directory in package function in PKGBUILD.proto

makepkg goes back to the $startdir between the build() and
package() functions so we need to change directory at the
start of the package function.

TODO: fix makepkg to make this unnecessary

Signed-off-by: Allan McRae <allan@archlinux.org>

PKGBUILD.proto

@@ -34,6 +34,8 @@ build() {
 }
 
 package() {
+  cd "$srcdir/$pkgname-$pkgver"
+
   make DESTDIR="$pkgdir/" install
 }