moves to an older version (0.7.4.201502262128) of JaCoCo.

The current maven plugin code doesn't work with 0.7.8, throwing the following error:

[ERROR] Failed to execute goal org.jacoco:jacoco-maven-plugin:0.7.8:report (post-unit-test) on project squelch: An error has occurred in JaCoCo report generation. Error while creating report: Cannot read execution data version 0x1006. This version of JaCoCo uses execution data version 0x1007. -> [Help 1]
Waiting for Jenkins to finish collecting data[ERROR]

This older version is reported to be compatible.