binary tarball: include cacert in root paths

93cc06334 removed nss-cacert from the binary tarball, but they're
necessary for global compatibility (and for our installer). This is what
results in cacerts being in the default profile, so e.g. the daemon has
TLS certs without having to use the system ones.

There's a fallback behavior in the daemon script in case these wind up
missing from the profile, but we don't want to have to rely on that,
since the fallback fails if it doesn't recognize one of a handful of
distros.

Change-Id: I60d8e6f734469548e80d5f38113ef168f67cbf7d

nix-support/binary-tarball.nix

@@ -1,11 +1,17 @@
 {
   buildPackages,
+  cacert,
   nix,
   system,
   version,
 }:
 let
-  installerClosureInfo = buildPackages.closureInfo { rootPaths = [ nix ]; };
+  installerClosureInfo = buildPackages.closureInfo {
+    rootPaths = [
+      nix
+      cacert
+    ];
+  };
 
   meta.description = "Distribution-independent Nix bootstrap binaries for ${system}";
 in