Use a git-format-patch instead of git-show for review

DPDK's checkpatches.sh seem to work better with files generated
by format-patch compared to piping git show into stdin.

Signed-off-by: Haggai Eran <haggaie@nvidia.com>

Author: haggaie

review.sh

@@ -4,7 +4,8 @@
 #set -x
 
 # Generate email style commit message
-PATCHMAIL=$(git show --format=email $1 | checkpatch.pl --no-tree -)
+PATCH_FILE=$(git format-patch $1 -1)
+PATCHMAIL=$(checkpatch.pl --no-tree $PATCH_FILE)
 
 # Internal state variables
 RESULT=0
@@ -101,4 +102,4 @@ else
     echo -e "\e[1;31m>> Failure\e[0m"
 fi
 
-exit $RESULT
+exit $RESULT