EvalSumRowsKeyGen()/EvalSumColsKeyGen() incorrect behavior

[dsuponitskiy]

We have moved all automorphism keys to one map (see issue #546 and issue #545). The code for EvalSumRowsKeyGen() and EvalSumColsKeyGen() was updated as well. However, these two functions return a map of the generated keys (unlike EvalSumKeyGen() which is "void"). This returned map is not fully (if at all) populated if the indices are added by calling EvalSumKeyGen(). An empty map passed as a parameter to a subsequent call to EvalSumRows() or EvalSumCols() throws an exception.