Adding options --nopresol, --noscale, --std to glpsol command gave me the same results as Rglpk_solve_lp.
glpsol --cpxlp ~/Downloads/PortfolioOptimization_minReturns_0.190000.lp -o output.sol --nopresol --noscale --std
I had to look into glpsol's code and compare it with Rglpk package's code to figure this out.