Remove the redundant null check expression of a non-null value lastResult.

[Kui-Liu]

The expression "lastResult != null" is a redundant check of a known non-null value because lastResult is non-null. http://findbugs.sourceforge.net/bugDescriptions.html#RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE

[coveralls]

Coverage decreased (-0.002%) to 89.961% when pulling 436f289a8ab79ed0c25eaa1b3acf67db6d2707d6 on BruceKuiLiu:master into eafb16c711d5cd79edad5fbb2055252acdb3825e on apache:master.

[coveralls]

Coverage decreased (-0.007%) to 89.956% when pulling 87abd8c27ba0405663abd0df209baee0b2148db7 on BruceKuiLiu:master into eafb16c711d5cd79edad5fbb2055252acdb3825e on apache:master.

[coveralls]

Coverage decreased (-0.002%) to 89.961% when pulling 87abd8c27ba0405663abd0df209baee0b2148db7 on BruceKuiLiu:master into eafb16c711d5cd79edad5fbb2055252acdb3825e on apache:master.

[coveralls]

Coverage remained the same at 89.963% when pulling 87ae52374d0a3fe149db4c4e02c83224f7f5ecc3 on BruceKuiLiu:master into eafb16c711d5cd79edad5fbb2055252acdb3825e on apache:master.

[coveralls]

Coverage remained the same at 89.963% when pulling d7f49057eb149e30dc77ed8286f7cfb32475f412 on BruceKuiLiu:master into eafb16c711d5cd79edad5fbb2055252acdb3825e on apache:master.

[coveralls]

Coverage decreased (-0.002%) to 89.961% when pulling d7f49057eb149e30dc77ed8286f7cfb32475f412 on BruceKuiLiu:master into eafb16c711d5cd79edad5fbb2055252acdb3825e on apache:master.