use else instead of else-if -- fixes 'possibly unused' warning

src/pathops/SkDQuadIntersection.cpp

Index: src/pathops/SkDQuadIntersection.cpp
diff --git a/src/pathops/SkDQuadIntersection.cpp b/src/pathops/SkDQuadIntersection.cpp
index 8b222f725d82661df928dffcdfa4f7d1717bc1a9..54c8b4979b7b72772414b71149358d2ead132556 100644
--- a/src/pathops/SkDQuadIntersection.cpp
+++ b/src/pathops/SkDQuadIntersection.cpp
@@ -175,7 +175,8 @@ static bool is_linear_inner(const SkDQuad& q1, double t1s, double t1e, const SkD
     double tMin, tMax;
     if (tCount == 1) {
         tMin = tMax = tsFound[0];
-    } else if (tCount > 1) {
+    } else {
+        SkASSERT(tCount > 1);
         SkTQSort<double>(tsFound.begin(), tsFound.end() - 1);
         tMin = tsFound[0];
         tMax = tsFound[tsFound.count() - 1];