Upgrade LevelDB to 1.14.0

LevelDB 1.14.0 changed the sstable extensions from sst to ldb. The old sst extension is still going to be recognised. 

See 1.14.0 change log on the link bellow:
https://code.google.com/p/leveldb/source/detail?r=0b9a89f40efdd143fa1426e7d5cd997f67ba6361

Ps.: MIPS build patch was also applied.