captureStdoutStderr*: move to Hydra::Helper::Exec which helps avoid some environment variable fixation problems

src/lib/Hydra/Helper/Nix.pm

@@ -18,8 +18,6 @@ use UUID4::Tiny qw(is_uuid4_string);
 our @ISA = qw(Exporter);
 our @EXPORT = qw(
     cancelBuilds
-    captureStdoutStderr
-    captureStdoutStderrWithStdin
     constructRunCommandLogPath
     findLog
     gcRootFor
@@ -429,30 +427,7 @@ sub pathIsInsidePrefix {
 }
 
 
-sub captureStdoutStderr {
-    my ($timeout, @cmd) = @_;
 
-    return captureStdoutStderrWithStdin($timeout, \@cmd, "");
-}
-
-sub captureStdoutStderrWithStdin {
-    my ($timeout, $cmd, $stdin) = @_;
-    my $stdout;
-    my $stderr;
-
-    eval {
-        local $SIG{ALRM} = sub { die "timeout\n" }; # NB: \n required
-        alarm $timeout;
-        IPC::Run::run($cmd, \$stdin, \$stdout, \$stderr);
-        alarm 0;
-        1;
-    } or do {
-        die unless $@ eq "timeout\n"; # propagate unexpected errors
-        return (-1, $stdout, ($stderr // "") . "timeout\n");
-    };
-
-    return ($?, $stdout, $stderr);
-}
 
 
 sub run {