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

BUG=
R=bsalomon@google.com

Review URL: https://codereview.chromium.org/18527003

git-svn-id: http://skia.googlecode.com/svn/trunk@9863 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pathops/SkDQuadIntersection.cpp b/src/pathops/SkDQuadIntersection.cpp
index 8b222f7..54c8b49 100644
--- a/src/pathops/SkDQuadIntersection.cpp
+++ b/src/pathops/SkDQuadIntersection.cpp
@@ -175,7 +175,8 @@
     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];