Fix randomly failing ping test on TargetPlatformServiceTest

com.sun.jersey.api.client.ClientHandlerException: java.net.SocketTimeoutException: Read timed out
	at java.net.SocketInputStream.socketRead0(Native Method)
	at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
	at java.net.SocketInputStream.read(SocketInputStream.java:170)
	at java.net.SocketInputStream.read(SocketInputStream.java:141)
	at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
	at java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
	at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
	at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:704)
	at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:647)
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1535)
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1440)
	at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480)
	at com.sun.jersey.client.urlconnection.URLConnectionClientHandler._invoke(URLConnectionClientHandler.java:253)
	at com.sun.jersey.client.urlconnection.URLConnectionClientHandler.handle(URLConnectionClientHandler.java:153)
	at com.sun.jersey.api.client.filter.HTTPBasicAuthFilter.handle(HTTPBasicAuthFilter.java:105)
	at com.sun.jersey.api.client.Client.handle(Client.java:652)
	at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682)
	at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74)
	at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:509)
	at org.nuxeo.targetplatforms.jaxrs.TargetPlatformServiceTest.ping(TargetPlatformServiceTest.java:46)