Fix field placeholder regression

src/components/views/auth/PasswordLogin.js

@@ -238,7 +238,7 @@ export default class PasswordLogin extends React.Component {
                     type="text"
                     label={_t("Phone")}
                     value={this.state.phoneNumber}
-                    prefix={phoneCountry}
+                    prefixComponent={phoneCountry}
                     onChange={this.onPhoneNumberChanged}
                     onBlur={this.onPhoneNumberBlur}
                     disabled={this.props.disableSubmit}

src/components/views/auth/RegistrationForm.js

@@ -473,7 +473,7 @@ export default createReactClass({
             type="text"
             label={phoneLabel}
             value={this.state.phoneNumber}
-            prefix={phoneCountry}
+            prefixComponent={phoneCountry}
             onChange={this.onPhoneNumberChange}
             onValidate={this.onPhoneNumberValidate}
         />;

src/components/views/elements/RoomAliasField.js

@@ -47,8 +47,8 @@ export default class RoomAliasField extends React.PureComponent {
                 <Field
                     label={_t("Room address")}
                     className="mx_RoomAliasField"
-                    prefix={poundSign}
-                    postfix={domain}
+                    prefixComponent={poundSign}
+                    postfixComponent={domain}
                     ref={ref => this._fieldRef = ref}
                     onValidate={this._onValidate}
                     placeholder={_t("e.g. my-room")}