ci: improve lcov HTML output

In particular, demangle C++ symbols in the function coverage view.

Change-Id: Ib8fd78a75cd79795795a040816da839775a11f53
diff --git a/.jenkins.d/00-deps.sh b/.jenkins.d/00-deps.sh
index 41b93f0..468075a 100755
--- a/.jenkins.d/00-deps.sh
+++ b/.jenkins.d/00-deps.sh
@@ -17,4 +17,9 @@
     sudo apt-get -qq update
     sudo apt-get -qq install build-essential pkg-config libboost-all-dev \
                              libcrypto++-dev libsqlite3-dev libssl-dev
+
+    if [[ $JOB_NAME == *"code-coverage" ]]; then
+        sudo apt-get -qq install lcov libgd-perl python-setuptools
+        sudo easy_install --upgrade gcovr
+    fi
 fi