Bug 1603746 - Check url for protocol at the beginning of the string r=chutten

Differential Revision: https://phabricator.services.mozilla.com/D57129

--HG--
extra : moz-landing-system : lando

toolkit/components/telemetry/pingsender/pingsender_unix_common.cpp

@@ -177,9 +177,9 @@ bool FallbackIsValidDestination(const string& aUrl) {
   std::transform(url.begin(), url.end(), url.begin(),
                  [](unsigned char c) { return std::tolower(c); });
   // Strip off the scheme in the beginning
-  if (url.find_first_of("http://") != std::string::npos) {
+  if (url.find("http://") == 0) {
     url = url.substr(7);
-  } else if (url.find_first_of("https://") != std::string::npos) {
+  } else if (url.find("https://") == 0) {
     url = url.substr(8);
   }