Qbs: Allow provider specification for plugins

Change-Id: I2016da500a9e81d8b2065c4c1c26a15d59c15abf
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>

qbs/pluginspec/pluginspec.qbs

@@ -7,7 +7,7 @@ Module {
     property int ide_version_minor: project.ide_version_minor
     property int ide_version_release: project.ide_version_release
     property string qtcreator_version: ide_version_major + '.' + ide_version_minor + '.' + ide_version_release
-    property string destdir: "lib/qtcreator/plugins/Nokia/"
+    property string destdir: product.destination
 
     FileTagger {
         pattern: "*.in"

src/plugins/QtcPlugin.qbs

@@ -3,7 +3,8 @@ import qbs.fileinfo 1.0 as FileInfo
 
 Product {
     type: ["dynamiclibrary", "pluginSpec"]
-    destination: "lib/qtcreator/plugins/Nokia"
+    property string provider: 'Nokia'
+    destination: "lib/qtcreator/plugins/" + provider
     targetName: {
         // see PluginSpecPrivate::loadLibrary()
         if (qbs.debugInformation) {