devtools: provide more generic grep in git check
devtools: provide more generic grep in git check

On Fedora 28, every patch is faulted for
"Wrong headline uppercase", because [A-Z] is not
always case sensitive.

Change to use [[:upper:]]

Signed-off-by: Andy Green <e3579b1e47f273529f0f929453e939a68ede9fd1@warmcat.com>
Tested-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk