Add pool_get_zero, pool_get_aligned_zero macros
Add pool_get_zero, pool_get_aligned_zero macros

Shorthand for the pattern:

   pool_get (<pool>, ep);
   memset (ep, 0, sizeof(*ep));

Should have done this years ago.

Change-Id: Ideeb27a79ff4ca3e9a077c973b297671d1fa2d26
Signed-off-by: Dave Barach <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@barachs.net>

chrisy/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp