Core: Add missing return

Amends 89702040cd

Change-Id: I2096c33dd3bb24a064a74b0356a29edc5859df11
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/plugininstallwizard.cpp

@@ -541,7 +541,7 @@ bool executePluginInstallWizard(const FilePath &archive)
 
                 QTC_ASSERT(specs.size() == 1, return false);
                 data.pluginSpec.reset(specs.front());
-
+                return true;
             } else {
                 QString error;
                 FileUtils::CopyAskingForOverwrite copy(ICore::dialogParent(), postCopyOperation());