hydra-server: Don't barf if the binary cache public key can't be read

Dependencies

• [2] V2YFPM72 Hackery to make downloads work when using a binary cache
• [3] LBNVQXUB * Build the /build stuff in a separate controller.

Change contents

• replacement in src/lib/Hydra/Controller/Build.pm at line 242
  [2.1021]→[2.1021:1235](∅→∅)
  − my $args =

  − defined $c->config->{binary_cache_public_key_file}

  − ? "--option binary-cache-public-keys " . read_file($c->config->{binary_cache_public_key_file}) . "\n"

  − : "";
  [2.1021]

  [2.1235]
  + my $args = "";

  + if (defined $c->config->{binary_cache_public_key_file}

  + && -r $c->config->{binary_cache_public_key_file})

  + {

  + $args = "--option binary-cache-public-keys " . read_file($c->config->{binary_cache_public_key_file});

  + }