devtools: fix ninja command in build test

devtools: fix ninja command in build test

On some linux distributions, eg: CentOS, the ninja executable has a
different name: ninja-build, this patch is to check and adapt to it
accordingly.

./devtools/test-meson-builds.sh: line 24: ninja: command not found

Fixes: a55277a788 ("devtools: add test script for meson builds")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Song Zhu <song.zhu@arm.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>