1.merge CONFIG_GIT_REVISION_STR into CONFIG_VERSION_BUILD
2.merge gen_getrev.sh into version.sh
3.generate version number if needed
Here is a sample output:
nsh> uname -a
NuttX 8.2 59fd8e12d3-dirty Dec 12 2019 15:48:00 sim sim
nsh> cat /proc/version
NuttX version 8.2 59fd8e12d3-dirty Dec 12 2019 15:48:01
report git info on /proc/gitrev
* report git info on /proc/gitrev
git info reported: branch, version, git hash, hostname, usr, build date
* use existing .version and procfs for git info
* reduce script's coupling
Approved-by: Gregory Nutt <gnutt@nuttx.org>
