ci: install gcovr via apt

Change-Id: I017ec6e4281a0348eca0361643cb3af0167c420f
Refs: #4771
diff --git a/.jenkins.d/00-deps.sh b/.jenkins.d/00-deps.sh
index aaa386c..beb2693 100755
--- a/.jenkins.d/00-deps.sh
+++ b/.jenkins.d/00-deps.sh
@@ -34,8 +34,7 @@
                              libsqlite3-dev libssl-dev
 
     if [[ $JOB_NAME == *"code-coverage" ]]; then
-        sudo apt-get -qy install lcov libgd-perl python-setuptools
-        sudo easy_install --upgrade gcovr
+        sudo apt-get -qy install gcovr lcov libgd-perl
     fi
 fi
 
diff --git a/.jenkins.d/30-coverage.sh b/.jenkins.d/30-coverage.sh
index 92f2bb8..46d3cf0 100755
--- a/.jenkins.d/30-coverage.sh
+++ b/.jenkins.d/30-coverage.sh
@@ -9,7 +9,7 @@
 if [[ $JOB_NAME == *"code-coverage" ]]; then
     gcovr --object-directory=build \
           --output=build/coverage.xml \
-          --filter="$PWD/ndn-cxx" \
+          --exclude="$PWD/(examples|tests)" \
           --root=. \
           --xml
 
diff --git a/.jenkins.d/README.md b/.jenkins.d/README.md
index a69ef9e..aeb94b0 100644
--- a/.jenkins.d/README.md
+++ b/.jenkins.d/README.md
@@ -27,7 +27,7 @@
   Possible values:
 
   * empty: default build process
-  * `code-coverage` (Linux OS is assumed): debug build with tests and code coverage analysis
+  * `code-coverage` (Ubuntu Linux is assumed): debug build with tests and code coverage analysis
   * `limited-build`: only a single debug build with tests
 
 - `WAF_JOBS`: number of parallel build jobs used by waf, defaults to 1.