Allow setting https host for trigger server.
Currently
connection = (HttpURLConnection) buildUrl.openConnection();
in RemoteBuildConfiguration will get a classcastException.

(Checking with our Jenkins ver. 1.609.1
setting https://test.jenkins.retail-sc.com/ as "Remote address and port"
fails with
{{java.net.MalformedURLException: no protocol: https%3A%2F%2Ftest.jenkins.retail-sc.com%2F%2Fjob%2Ftest-1-run%2Fapi%2Fjson
at java.net.URL.<init>(URL.java:585)
at java.net.URL.<init>(URL.java:482)
at java.net.URL.<init>(URL.java:431)
at org.jenkinsci.plugins.ParameterizedRemoteTrigger.RemoteBuildConfiguration.sendHTTPCall(RemoteBuildConfiguration.java:699)
at org.jenkinsci.plugins.ParameterizedRemoteTrigger.RemoteBuildConfiguration.sendHTTPCall(RemoteBuildConfiguration.java:672)
at org.jenkinsci.plugins.ParameterizedRemoteTrigger.RemoteBuildConfiguration.isRemoteJobParameterized(RemoteBuildConfiguration.java:916)
at org.jenkinsci.plugins.ParameterizedRemoteTrigger.RemoteBuildConfiguration.perform(RemoteBuildConfiguration.java:482)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:761)
at hudson.model.Build$BuildExecution.build(Build.java:203)
at hudson.model.Build$BuildExecution.doRun(Build.java:160)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:536)
at hudson.model.Run.execute(Run.java:1741)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:374)

}}