There's a bug in the HttpClient library. When reading the response headers, it keeps an eye out for the Content-length header, and does this by comparing the current header text to a string pointer to "Content-length". The bug is that the string pointer is intialized to 0 instead of the to text "Content-length". On simple devices like Arduino this is not fatal. Obviously, it's broken and doesn't work as intended, but it executes, just not correctly. On Galileo, though, which has a CPU running in protected mode, reading from a NULL pointer is verboten and it generates a segmentation fault which causes the sketch to crash.
I have notified the developer. The fix is rather simple. In the resetState() function in HttpClient.cpp, change the initialization of iContentLengthPtr to point to the right thing instead of 0:
iContentLengthPtr= kContentLengthPrefix;
This is line 44 in the current source tree (as of 5/14/14).