build-unit-test-docker: Build sdeventplus with meson

sdeventplus is moving to meson, so we should build it that way for our
project cache.

Tested:
    Builds and installs files that are usable by dependencies.

Change-Id: I238f69a74bae80b8818724776bd203fbc8b18eb1
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index 0d92880..6591805 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -288,10 +288,9 @@
 FROM openbmc-base as openbmc-sdeventplus
 RUN curl -L https://github.com/openbmc/sdeventplus/archive/${PKG_REV['sdeventplus']}.tar.gz | tar -xz && \
 cd sdeventplus-* && \
-./bootstrap.sh && \
-./configure ${CONFIGURE_FLAGS[@]} --disable-tests --disable-examples && \
-make -j$(nproc) && \
-make install
+meson build -Dprefix=${PREFIX} -Dtests=disabled -Dexamples=false && \
+ninja -C build && \
+ninja -C build install
 
 FROM openbmc-base as openbmc-gpioplus
 RUN curl -L https://github.com/openbmc/gpioplus/archive/${PKG_REV['gpioplus']}.tar.gz | tar -xz && \