Skip blank lines in IniFile::GetKeys().
Skip blank lines in IniFile::GetKeys().

Fixes hrydgard/ppsspp#3783.

unknownbrackets/native,hrydgard/native,zhykzhykzhyk/ppsspp-native,libretro/ppsspp-native,unknownbrackets/native,libretro/ppsspp-native,zhykzhykzhyk/ppsspp-native,hrydgard/native,zhykzhykzhyk/ppsspp-native,zhykzhykzhyk/ppsspp-native,libretro/ppsspp-native,hrydgard/native,unknownbrackets/native,hrydgard/native,libretro/ppsspp-native,unknownbrackets/native