fix: usr: #300: Modify getStats() in NonLocalRequestChain to report correct Cache Stats

[garvit-gupta]

• NonLocalRequestChain.getStats() was reporting all requests as remote reads which is wrong.

• Marking those requests that go to the NonLocalReadRequestChain as nonlocal reads with this change.

• The rest of the requests that go to the RemoteFetchRequestChain result in data getting downloaded asynchronously in the non-local node, while the requesting node falls back to direct reads, and direct reads stats are not collected.

fixes #300

[codecov-io]

Codecov Report

Merging #301 into master will increase coverage by 0.06%. The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #301      +/-   ##
==========================================
+ Coverage   50.31%   50.37%   +0.06%     
==========================================
  Files          60       60              
  Lines        3031     3033       +2     
  Branches      332      333       +1     
==========================================
+ Hits         1525     1528       +3     
+ Misses       1417     1415       -2     
- Partials       89       90       +1

Impacted Files	Coverage Δ
...va/com/qubole/rubix/core/NonLocalRequestChain.java	0% <0%> (ø)	:arrow_up:
.../qubole/rubix/hadoop2/Hadoop2ClusterManagerV2.java	52.63% <0%> (+5.26%)	:arrow_up: