Fixed small typo in marker.c

Change-Id: Iec89e7141f6ff3216355d8a6b971617e16df679b
BUG: 1075417
Signed-off-by: Jan-Hendrik Zab <zab@l3s.de>
Reviewed-on: http://review.gluster.org/9238
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>