Bug in 2ls k-induction

[rajdeep87]

K-induction proof seems to be buggy in 2ls. The following benchmark reproduce the bug.
https://github.com/rajdeep87/verilog-c/tree/master/safe/hwmcc15/6s177

@peterschrammel The proof fails showing "k-induction counterexample found after 0 unwinding(s)". However, CBMC proves it safe for 100 unwindings. Also, the benchmark is SAFE for more than 100 unwindings.
Command line option used : --k-induction --inline --havoc --competition mode