removed the duplicate calls of functions

Removed the duplicate call of drop_mongocollection and mongodb_inserts_benchmark functions. This is was making the function run for long time.
Merge pull request #4 from vibhorkum/patch-3

Removing the duplicate measurement runs.

Ideally, this shouldn't affect the reported numbers as compared to version 2.0. Just the total run
time of the script will be affected. To account for this change, the version number has also been
bumped.