Hardcoded threshold values in check-ram.rb override command line values

[jaykumar-jnpr]

Following line override warning and critical threshold set when using "-u" or "--used" memory values.

L88 config[:warn] = 90
L89 config[:crit] = 95

If the current memory usage is at 91% and threshold as set as follows, it will not alert as threshold set on command line are overridden by above two lines

/opt/sensu/embedded/bin/ruby check-ram.rb --used -w 80 -c 90

Expected behaviour:

CheckRAM CRITICAL: 91% RAM used

Actual

CheckRAM WARNING: 91% RAM used