wrap: detect network timeouts 20x faster

When downloading wrap content, we need to know at some point if the
server is going to respond with "hello, yes, I'm here and I have data
for you". The alternative is to sometimes infinitely hang.

In commit 8f7781f1d6 we added such a
timeout, but using an extremely generously high number -- ten minutes.
We don't need to wait this long just to find out if the other end
exists, so decrease that time to 30 seconds, whch is still ludicrously
generous but not quite as much so.

mesonbuild/wrap/wrap.py

@@ -54,7 +54,7 @@ try:
 except ImportError:
     has_ssl = False
 
-REQ_TIMEOUT = 600.0
+REQ_TIMEOUT = 30.0
 WHITELIST_SUBDOMAIN = 'wrapdb.mesonbuild.com'
 
 ALL_TYPES = ['file', 'git', 'hg', 'svn']