Several of the error exits from libxl_ctx_alloc leaked the context
struct itself and sometimes other resources too.
Fix this by using the standard "rc = ERROR_FOO; goto out" error
handling style throughout.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>