expect kexec: 'kexec_core: Starting new kernel' also valid
expect kexec: 'kexec_core: Starting new kernel' also valid

Some kernels display 'kexec_core: Starting new kernel' to indicate
we're doing a kexec, so we should also expect that.

Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

open-power/op-test-framework,open-power/op-test-framework,open-power/op-test-framework