Fix for MULE-5512 org.mule.endpoint.URIBuilder prevent the use of expres...

There is a IMHO excessively defensive implementation of the "path" parser. In URIBuilder.java we can find :
public void setPath(String path)
...
if (path.indexOf(DOTS_SLASHES) > -1)
{ throw new IllegalArgumentException("Unusual syntax in path: '" + path + "' contains " + DOTS_SLASHES); }
This should not be done of done after exploding expressions. With this check something as simple as :
<http:outbound-endpoint host="localhost" port="8080" path="#[xpath://whatever]" />
Won't work because of the "//".