MDEV-30374 Windows, MSI - do not cache error, if install directory changes.

If installation directory is not empty, MSI would shows a popup informing
user about it. The error message is stored as MSI property
INSTALLDIRERROR.

Fixed the bug that the error was not cleared, when the user changes
directory in installer UI.

Author: vaintroub

win/packaging/ca/CustomAction.cpp

@@ -202,7 +202,11 @@ extern "C" UINT __stdcall CheckInstallDirectory(MSIHANDLE hInstall)
     swprintf(msg,countof(msg), L"Installation directory '%s' exists and is not empty. Choose a "
                   "different install directory",path);
     WcaSetProperty(L"INSTALLDIRERROR", msg);
+    goto LExit;
   }
+
+  WcaSetProperty(L"INSTALLDIRERROR", L"");
+
 LExit:
   ReleaseStr(path);
   return WcaFinalize(er);