When building the connection URI in Hypervisor.java, the query parameter "?no_tty=1" is always appended. This does not take into account, that users might already have added their own parameters in the advanced settings already.
E.g: In order to use a different SSH-key location and disable host-key verification, I use the following Hypervisor-System-URL:
The attached patch fixes this by using '&' resp. '?' conditionally.
Please note, that the patch also contains an update in the (rather old) plugin's pom.xml to make it build with current jenkins (and JDK 1.7).