[Observium] Wiki fix: spikes

I didn't see how I can edit it so: http://www.observium.org/wiki/Removing_RRDTool_Spikes

for i in rrds/*/*.rrd; do scripts/removespikes.pl $i; done; should be for i in rrd/*/*.rrd; do scripts/removespikes.pl $i; done;

Changes: rrds -> rrd