p4c-dpdk --version output is less informative than other p4c back ends

[jafingerhut]

I just happened to notice this today when checking versions of binaries installed for different back ends:

andy@andy-vm:~$ p4c-bm2-psa --version
p4c-bm2-psa
Version 0.0.1 (SHA: a9aa5ff)
andy@andy-vm:~$ p4c-bm2-ss --version
p4c-bm2-ss
Version 1.2.2 (SHA: a9aa5ff BUILD: RELEASE)
andy@andy-vm:~$ p4c-ebpf --version
p4c-ebpf
Version 1.2.2 (SHA: a9aa5ff BUILD: RELEASE)
andy@andy-vm:~$ p4c-graphs --version
p4c-graphs
Version 1.2.2 (SHA: a9aa5ff BUILD: RELEASE)
andy@andy-vm:~$ p4test --version
p4test
Version 1.2.2 (SHA: a9aa5ff BUILD: RELEASE)
andy@andy-vm:~$ p4c-dpdk --version
p4c-dpdk
Version 0.1

In particular, the SHA is very useful for P4 developers when they are diagnosing bugs that might be fixed recently.