Fix a memory leak reported by clang static analyzer.

src/ports/SkOSFile_stdio.cpp

Index: src/ports/SkOSFile_stdio.cpp
diff --git a/src/ports/SkOSFile_stdio.cpp b/src/ports/SkOSFile_stdio.cpp
index f0082838045bff04ee2a4d0635558e43004a6225..6d39b3afd19a44a48cdb310523d1e4571d54ef59 100644
--- a/src/ports/SkOSFile_stdio.cpp
+++ b/src/ports/SkOSFile_stdio.cpp
@@ -31,6 +31,7 @@ static FILE* ios_open_from_bundle(const char path[], const char* perm) {
     // Get a reference to the file's URL
     CFStringRef pathRef = CFStringCreateWithCString(NULL, path, kCFStringEncodingUTF8);
     CFURLRef imageURL = CFBundleCopyResourceURL(mainBundle, pathRef, NULL, NULL);
+    CFRelease(pathRef);
     if (!imageURL) {
         return nullptr;
     }