Don't leak HttpGet objects in ZipInstaller.

When creating a new HttpGet object schedule any old one for deletion instead of
dropping its reference and relying on Qt to clean it up once the parent object
is removed.

Change-Id: I66f2a6f01c6b6ad3a0dce0eb4fd3eacfaf7e733d

rbutil/rbutilqt/base/zipinstaller.cpp

@@ -25,6 +25,7 @@ ZipInstaller::ZipInstaller(QObject* parent): QObject(parent)
 {
     m_unzip = true;
     m_usecache = false;
+    getter = 0;
 }
 
 
@@ -87,6 +88,7 @@ void ZipInstaller::installStart()
     m_file = downloadFile->fileName();
     downloadFile->close();
     // get the real file.
+    if(getter != 0) getter->deleteLater();
     getter = new HttpGet(this);
     if(m_usecache) {
         getter->setCache(true);