Make it easier to override path to asciidoc command
Make it easier to override path to asciidoc command

Allow setting the path of asciidoc in only one place when creating
the documentation.

Signed-off-by: Dotan Barak <b3b47477f528a5bde0a5a6bab57b60b3c423571a@dev.mellanox.co.il>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git