Actually check the return values of the various Coin* calls

...the code had been like this ever since it got introduced with
6d492447 "118160: Use CoinMP as replacement for
lp_solve," but it looks more plausible that the return values should be checked
rather than be ignored.  At least, CppunitTest_sccomp_lpsolver keeps succeeding
after the change (with --enable-coinmp).

Change-Id: If450827ae034079c9ee69b4e49c55b480ac0de06

sccomp/source/solver/CoinMPSolver.cxx

@@ -294,7 +294,10 @@ void SAL_CALL CoinMPSolver::solve() throw(uno::RuntimeException, std::exception)
                     pLowerBounds, pUpperBounds, pRowType, pRHS, NULL,
                     pMatrixBegin, pMatrixCount, pMatrixIndex, pMatrix,
                     NULL, NULL, NULL );
+    if (nResult == SOLV_CALL_SUCCESS)
+    {
         nResult = CoinLoadInteger( hProb, pColType );
+    }
 
     delete[] pColType;
     delete[] pMatrixIndex;
@@ -314,8 +317,13 @@ void SAL_CALL CoinMPSolver::solve() throw(uno::RuntimeException, std::exception)
 
     // solve model
 
+    if (nResult == SOLV_CALL_SUCCESS)
+    {
         nResult = CoinCheckProblem( hProb );
+    }
 
+    if (nResult == SOLV_CALL_SUCCESS)
+    {
         try
         {
             nResult = CoinOptimizeProblem( hProb, 0 );
@@ -324,6 +332,7 @@ void SAL_CALL CoinMPSolver::solve() throw(uno::RuntimeException, std::exception)
         {
             throw std::runtime_error(e.message());
         }
+    }
 
     mbSuccess = ( nResult == SOLV_CALL_SUCCESS );
     if ( mbSuccess )