Git/VCS: Use ctrlc stub for process execution

This ensures that child processes are also terminated.

Required specifically for Git on Windows, when running in cmd directory,
which spawns a child process for usr/bin/git. On this case, if git takes
long to finish and is aborted while running, the main process was killed
as expected, but the child process remained alive.

Task-number: QTCREATORBUG-27567
Change-Id: I40271eb42cfaefd81f2fe5af138254ab0a2c8da8
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/git/branchmodel.cpp

@@ -885,6 +885,7 @@ void BranchModel::updateUpstreamStatus(BranchNode *node)
     process->setCommand({d->client->vcsBinary(), {"rev-list", "--no-color", "--left-right",
                          "--count", node->fullRef() + "..." + node->tracking}});
     process->setWorkingDirectory(d->workingDirectory);
+    process->setUseCtrlCStub(true);
     connect(process, &QtcProcess::done, this, [this, process, node] {
         process->deleteLater();
         if (process->result() != ProcessResult::FinishedWithSuccess)

src/plugins/git/changeselectiondialog.cpp

@@ -213,6 +213,7 @@ void ChangeSelectionDialog::recalculateCompletion()
     process->setEnvironment(client->processEnvironment());
     process->setCommand({client->vcsBinary(), {"for-each-ref", "--format=%(refname:short)"}});
     process->setWorkingDirectory(workingDir);
+    process->setUseCtrlCStub(true);
     connect(process, &QtcProcess::done, this, [this, process] {
         if (process->result() == ProcessResult::FinishedWithSuccess)
             m_changeModel->setStringList(process->cleanedStdOut().split('\n'));

src/plugins/git/gerrit/gerritmodel.cpp

@@ -248,6 +248,7 @@ QueryContext::QueryContext(const QString &query,
                            QObject *parent)
     : QObject(parent)
 {
+    m_process.setUseCtrlCStub(true);
     if (server.type == GerritServer::Ssh) {
         m_binary = p->ssh;
         if (server.port)

src/plugins/git/gerrit/gerritplugin.cpp

@@ -119,6 +119,7 @@ FetchContext::FetchContext(const QSharedPointer<GerritChange> &change,
     , m_server(server)
     , m_state(FetchState)
 {
+    m_process.setUseCtrlCStub(true);
     connect(&m_process, &QtcProcess::done, this, &FetchContext::processDone);
     connect(&m_process, &QtcProcess::readyReadStandardError,
             this, &FetchContext::processReadyReadStandardError);

src/plugins/vcsbase/vcscommand.cpp

@@ -114,6 +114,7 @@ void VcsCommandPrivate::setupProcess(QtcProcess *process, const Job &job)
         process->setProcessChannelMode(QProcess::MergedChannels);
     if (m_codec)
         process->setCodec(m_codec);
+    process->setUseCtrlCStub(true);
 
     installStdCallbacks(process);