ipfs: avoid warning during build when moving directory

Trying to move a directory into itself will result in a warning:
mv: cannot move 'ipfs-src' to a subdirectory of itself, 'ipfs-src/ipfs-src'

This can be prevented by excluding that directory.

pkgs/applications/networking/ipfs/default.nix

@@ -14,7 +14,8 @@ buildGoModule rec {
   # tarball contains multiple files/directories
   postUnpack = ''
     mkdir ipfs-src
-    mv * ipfs-src || true
+    shopt -s extglob
+    mv !(ipfs-src) ipfs-src || true
     cd ipfs-src
   '';