Automatic merge from submit-queue (batch tested with PRs 59653, 58812, 59582, 59665, 59511). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

libffi-dev dependency added in fluentd-es-image Dockerfile to solve the docker build error

**What this PR does / why we need it**:

Not able to build the docker images for fluentd-es-image. The docker build shows the error like below

```
Installing fluent-plugin-elasticsearch (2.4.1)
Installing ffi (1.9.21)
Building native extensions.  This could take a while...
ERROR:  While executing gem ... (Gem::Ext::BuildError)
    ERROR: Failed to build gem native extension.

    current directory: /var/lib/gems/2.3.0/gems/ffi-1.9.21/ext/ffi_c
/usr/bin/ruby2.3 -r ./siteconf20180209-4127-3e9tjv.rb extconf.rb
checking for ffi.h... no
checking for ffi.h in /usr/local/include,/usr/include/ffi... no
checking for shlwapi.h... no
checking for rb_thread_blocking_region()... no
checking for rb_thread_call_with_gvl()... yes
checking for rb_thread_call_without_gvl()... yes
creating extconf.h
creating Makefile

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/ffi-1.9.21/mkmf.log

current directory: /var/lib/gems/2.3.0/gems/ffi-1.9.21/ext/ffi_c
make "DESTDIR=" clean

current directory: /var/lib/gems/2.3.0/gems/ffi-1.9.21/ext/ffi_c
make "DESTDIR="
Running autoreconf for libffi
/var/lib/gems/2.3.0/gems/ffi-1.9.21/ext/ffi_c/libffi/autogen.sh: 2: exec: autoreconf: not found
libffi.mk:6: recipe for target '"/var/lib/gems/2.3.0/gems/ffi-1.9.21/ext/ffi_c/libffi-x86_64-linux-gnu"/.libs/libffi_convenience.a' failed
make: *** ["/var/lib/gems/2.3.0/gems/ffi-1.9.21/ext/ffi_c/libffi-x86_64-linux-gnu"/.libs/libffi_convenience.a] Error 127

make failed, exit code 2

Gem files will remain installed in /var/lib/gems/2.3.0/gems/ffi-1.9.21 for inspection.
Results logged to /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/ffi-1.9.21/gem_make.out
The command '/bin/sh -c BUILD_DEPS="make gcc g++ libc6-dev ruby-dev"     && clean-install $BUILD_DEPS                      ca-certificates                      libjemalloc1                      ruby     && echo 'gem: --no-document' >> /etc/gemrc     && gem install --file Gemfile     && apt-get purge -y --auto-remove                      -o APT::AutoRemove::RecommendsImportant=false                      $BUILD_DEPS     && clean-apt     && ulimit -n 65536' returned a non-zero code: 1
```
added the libffi-dev dependency solves the build error.


```release-note
NONE
```