Fix string assert and dead code which caused it.

tools/flags/SkCommandLineFlags.cpp

Index: tools/flags/SkCommandLineFlags.cpp
diff --git a/tools/flags/SkCommandLineFlags.cpp b/tools/flags/SkCommandLineFlags.cpp
index 42e9ebd971da2d59120b4a9b8f85e83b643c0c9a..c25fec5343cb04f2b3744c248b163a314090b80e 100644
--- a/tools/flags/SkCommandLineFlags.cpp
+++ b/tools/flags/SkCommandLineFlags.cpp
@@ -287,10 +287,6 @@ void SkCommandLineFlags::Parse(int argc, char** argv) {
                 flag = flag->next();
             }
             if (!flagMatched) {
-                SkString stripped(argv[i]);
-                while (stripped.startsWith('-')) {
-                    stripped.remove(0, 1);
-                }
                 if (!FLAGS_undefok) {
                     SkDebugf("Got unknown flag \"%s\". Exiting.\n", argv[i]);
                     exit(-1);