doc install: fix Yum repository RPM URL
doc install: fix Yum repository RPM URL

yoku0825/mroonga,mroonga/mroonga,mroonga/mroonga,naoa/mroonga,yoku0825/mroonga,yoku0825/mroonga,naoa/mroonga,yoku0825/mroonga,naoa/mroonga,naoa/mroonga,mroonga/mroonga,naoa/mroonga,yoku0825/mroonga,naoa/mroonga,yoku0825/mroonga,mroonga/mroonga