Revert of Have GrRectBlurEffect use Linear filtering (rather than Nearest Neighbor)

src/effects/SkBlurMask.cpp

Index: src/effects/SkBlurMask.cpp
diff --git a/src/effects/SkBlurMask.cpp b/src/effects/SkBlurMask.cpp
index 1445c7cb132bd720ba76fdeed2e1b6d2d303a9eb..acee70ff254afe85ff88fb03aaa608d5d8112cf7 100644
--- a/src/effects/SkBlurMask.cpp
+++ b/src/effects/SkBlurMask.cpp
@@ -681,7 +681,7 @@
 uint8_t* SkBlurMask::ComputeBlurProfile(SkScalar sigma) {
     int size = SkScalarCeilToInt(6*sigma);
 
-    float center = 0.5f * size;
+    int center = size >> 1;
     uint8_t* profile = new uint8_t[size];
 
     float invr = 1.f/(2*sigma);