Allow specifying https-keystore without https-port

WireMock can now proxy HTTPS over its HTTP port. This means it's valid to
provide a keystore to configure how that HTTPS is encrypted despite not
listening for HTTPS directly.

Author: Mahoney

Diff for: src/main/java/com/github/tomakehurst/wiremock/standalone/CommandLineOptions.java

@@ -171,9 +171,6 @@ private void validate() {
         if (!optionSet.has(HTTPS_PORT) && optionSet.has(DISABLE_HTTP)) {
             throw new IllegalArgumentException("HTTPS must be enabled if HTTP is not.");
         }
-        if (optionSet.has(HTTPS_KEYSTORE) && !optionSet.has(HTTPS_PORT)) {
-            throw new IllegalArgumentException("HTTPS port number must be specified if specifying the keystore path");
-        }
 
         if (optionSet.has(RECORD_MAPPINGS) && optionSet.has(DISABLE_REQUEST_JOURNAL)) {
             throw new IllegalArgumentException("Request journal must be enabled to record stubs");

Diff for: src/test/java/com/github/tomakehurst/wiremock/standalone/CommandLineOptionsTest.java

@@ -127,11 +127,6 @@ public void setsKeyStorePathAndPassword() {
         assertThat(options.httpsSettings().keyStorePassword(), is("someotherpwd"));
     }
 
-    @Test(expected=IllegalArgumentException.class)
-    public void throwsExceptionIfKeyStoreSpecifiedWithoutHttpsPort() {
-        new CommandLineOptions("--https-keystore", "/my/keystore");
-    }
-
 	@Test(expected=Exception.class)
 	public void throwsExceptionWhenPortNumberSpecifiedWithoutNumber() {
 		new CommandLineOptions("--port");