bitbake: fetch2: handle empty elements in _param_str_split

_param_str_split is used to split ?foo=1;bar=2 into a dictionary, but throws
an exception if a lone semicolon is used as the value doesn't split into two
items.

Fix by checking that the result of the first split has content.

(Bitbake rev: 7662f8c8676d87cb318f811423cc02fe8cb146f6)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/fetch2/__init__.py

@@ -290,7 +290,7 @@ class URI(object):
 
     def _param_str_split(self, string, elmdelim, kvdelim="="):
         ret = collections.OrderedDict()
-        for k, v in [x.split(kvdelim, 1) for x in string.split(elmdelim)]:
+        for k, v in [x.split(kvdelim, 1) for x in string.split(elmdelim) if x]:
             ret[k] = v
         return ret