[libvirt] Power Hypervisor: Fix potential segfault and memleak in phypOpen

Hi, I came across this line in the phypOpen function: char string[strlen(conn->uri->path)]; Here the path part of the given URI is used without checking it for NULL, this can cause a segfault as strlen expects a string != NULL. Beside that uuid_db and connection_data leak in case of an error. In this line conn->uri->path = string; the original path of the URI leaks. The patch adds a VIR_FREE call before setting the new path. The attached patch is compile-tested but I don't have a Power Hypervisor installation at hand to test it for real. Matthias