Fix inconsistent spaces vs tabs indent in makefile
Fix inconsistent spaces vs tabs indent in makefile

The makefile guidelines say to use tabs instead of spaces. This commit
makes the file consistent with these guidelines whenever possible, as
long as it does not impact the visual alignment of elements.

Signed-off-by: Federico Morg Pareschi <ff862f58af48d157b995cd83870fbfa4aec8edf3@google.com>
Reviewed-by: Brian Foley <a00e555871a6a538e97f8c44307104c884f8e869@google.com>

yiannist/ganeti,ganeti/ganeti,mbakke/ganeti,mbakke/ganeti,mbakke/ganeti,onponomarev/ganeti,onponomarev/ganeti,yiannist/ganeti,andir/ganeti,yiannist/ganeti,ganeti/ganeti,ganeti/ganeti,andir/ganeti,andir/ganeti