title: Branch coverage is not shown in Sonarcloud when syncing with master branch
body: <p>I'm trying to run analysis on my code using <b>jacoco</b> plugin in <b>gradle</b> and <b>sonarqube</b>. My tests are written in <b>Groovy</b>. I've automated the process using bitbucket pipelines, so every time I commit code, the tests are run, and the jacoco analysis and sonarqube are run in the end, pushing the report results in SonarCloud. Coverage is shown (as a percentage, with a link to classes) and compared against dev branch (I explicitly specified dev as a long-lived branch in SonarCloud). Also, overall coverage is shown (after merge). </p>
  
  <p>The problem is, when I merge dev into my branch (something else gets merged to dev, so I sync), then, the branch coverage is shown as "-", i.e. empty. I can't seem to find the problem, rather than guessing that the commit (that comes from merging dev into my branch), has 2 parents (the previous commit and another short-lived branch which was merged in dev), and somehow it gets confused. 
  After I commit something, even a silly line of code, then the analysis is shown yet again, correctly.</p>
  
  <p>I'd like to know if anybody has solved this issue, or knows why it happens. Thanks!</p>
  
  <p>In build.gradle I've added:</p>
  
  <pre class="lang-java prettyprint-override"><code> plugins {
      id "org.springframework.boot" version "2.0.2.RELEASE"
      id "org.sonarqube" version "2.7.1"
      id "application"
      id "jacoco"
  }
  
  apply plugin: 'java'
  apply plugin: 'groovy'
  apply plugin: 'jacoco'
  
  jacoco {
      toolVersion = "0.8.3"
      reportsDir = file("$buildDir/customJacocoReportDir")
  }
  
  jacocoTestReport {
      reports {
          xml.enabled false
          csv.enabled false
          html.destination file("$buildDir/jacocoHtml")
      }
  }
  
  sonarqube {
     properties {
          // properties related to credentials
      }
  }
  
  </code></pre>
  
  <p>and my bitbucket pipelines file is:</p>
  
  <pre class="lang-java prettyprint-override"><code>image: java:8
  
  clone:
    depth: full  # SonarCloud scanner needs the full history to assign issues properly
  
  definitions:
    caches:
      sonar: ~/.sonar/cache  # Caching SonarCloud artifacts will speed up your build
    steps:
      - step: &amp;build-test-sonarcloud
          name: Build, test and analyze on SonarCloud
          caches:
            - gradle
            - sonar
          script:
            - ./gradlew clean test
            - ./gradlew jacocoTestReport
            - ./gradlew sonarqube
          artifacts:
            - build/libs/**
  
  pipelines:
    default:
      - step: *build-test-sonarcloud
    pull-requests:
      '**':
        - step: *build-test-sonarcloud
  </code></pre>