Fix metrics counter reporting.

[vkryachko]

The issue was that we were never resetting counters after a successful
metrics upload. This resulted in ever increasing counter values that did
not represent reality.

[google-oss-bot]

Coverage Report

Affected SDKs

• transport-runtime

  SDK overall coverage changed from 55.31% (8068a9b) to 55.40% (72128d72) by +0.09%.

  Filename	Base (8068a9b)	Head (72128d72)	Diff
  Uploader.java	94.74%	94.95%	+0.21%

Test Logs

• Base (8068a9ba): https://android-ci.firebaseopensource.com/view/gcs/android-ci/logs/postsubmit-check-coverage/1458508305784639492
• Head (72128d72): https://android-ci.firebaseopensource.com/view/gcs/android-ci/pr-logs/pull/firebase_firebase-android-sdk/3128/check-coverage-changed/1458823487958290435

Notes

HTML coverage reports can be produced locally with ./gradlew <product>:checkCoverage.
Report files are located at <product-build-dir>/reports/jacoco/.

Head commit (72128d72) is created by Prow via merging commits: 8068a9b 270ed12.

[google-oss-bot]

Binary Size Report

Affected SDKs

• transport-runtime

  Type	Base (8068a9b)	Head (72128d72)	Diff
  aar	178 kB	178 kB	+158 B (+0.1%)
  apk (aggressive)	43.5 kB	43.8 kB	+216 B (+0.5%)
  apk (release)	82.4 kB	82.6 kB	+140 B (+0.2%)

Test Logs

• Base (8068a9ba): https://android-ci.firebaseopensource.com/view/gcs/android-ci/logs/postsubmit-binary-size/1458508305784639493
• Head (72128d72): https://android-ci.firebaseopensource.com/view/gcs/android-ci/pr-logs/pull/firebase_firebase-android-sdk/3128/binary-size/1458823487962484736

Notes

Head commit (72128d72) is created by Prow via merging commits: 8068a9b 270ed12.

[vkryachko]

/retest

[vkryachko]

/retest

[google-oss-bot]

@vkryachko: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
device-check-changed	270ed12	link	/test device-check-changed

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.