Move _run_command method to mysql class

The Pg class doesn't need this at all

lib/Database/Migrator/Core.pm

@@ -189,45 +189,6 @@ sub _run_one_migration {
     return;
 }
 
-sub _run_command {
-    my $self    = shift;
-    my $command = shift;
-    my $input   = shift;
-
-    my $stdout = q{};
-    my $stderr = q{};
-
-    my $handle_stdout = sub {
-        $self->logger()->debug(@_);
-
-        $stdout .= $_ for @_;
-    };
-
-    my $handle_stderr = sub {
-        $self->logger()->debug(@_);
-
-        $stderr .= $_ for @_;
-    };
-
-    $self->logger()->debug("Running command: [@{$command}]");
-
-    return if $self->dry_run();
-
-    run3( $command, \$input, $handle_stdout, $handle_stderr );
-
-    if ($?) {
-        my $exit = $? >> 8;
-
-        my $msg = "@{$command} returned an exit code of $exit\n";
-        $msg .= "\nSTDOUT:\n$stdout\n\n" if length $stdout;
-        $msg .= "\nSTDERR:\n$stderr\n\n" if length $stderr;
-
-        die $msg;
-    }
-
-    return $stdout;
-}
-
 sub _build_pending_migrations {
     my $self = shift;