Properly generate electron dependencies in test Dockerfile from template

templates/tools/dockerfile/test/node_jessie_x64/Dockerfile.template

@@ -28,10 +28,21 @@
   # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-  
+
   FROM debian:jessie
-  
+
   <%include file="../../apt_get_basic.include"/>
+
+  # Install Electron apt dependencies
+  RUN apt-get update && apt-get install -y ${'\\'}
+    libasound ${'\\'}
+    libgconf-2-4 ${'\\'}
+    libgtk2.0-0 ${'\\'}
+    libnss3 ${'\\'}
+    libxss1 ${'\\'}
+    libxtst6 ${'\\'}
+    xvfb
+
   <%include file="../../python_deps.include"/>
   <%include file="../../node_deps.include"/>
   <%include file="../../run_tests_addons.include"/>

tools/dockerfile/test/node_jessie_x64/Dockerfile

@@ -42,18 +42,12 @@ RUN apt-get update && apt-get install -y \
   git \
   golang \
   gyp \
-  libasound2 \
   lcov \
   libc6 \
   libc6-dbg \
   libc6-dev \
-  libgconf-2-4 \
   libgtest-dev \
-  libgtk2.0-0 \
-  libnss3 \
   libtool \
-  libxss1\
-  libxtst6 \
   make \
   perl \
   strace \
@@ -63,13 +57,23 @@ RUN apt-get update && apt-get install -y \
   telnet \
   unzip \
   wget \
-  xvfb \
   zip && apt-get clean
 
 #================
 # Build profiling
 RUN apt-get update && apt-get install -y time && apt-get clean
 
+
+# Install Electron apt dependencies
+RUN apt-get update && apt-get install -y \
+  libasound \
+  libgconf-2-4 \
+  libgtk2.0-0 \
+  libnss3 \
+  libxss1 \
+  libxtst6 \
+  xvfb
+
 #====================
 # Python dependencies