bitbake: server/process: Add missing exception raise

The intent of the code was to catch one kind of error, it was actually swallowing
all exceptions and looping indefinitely. Fix it to work as intended.

This explains some mystery hangs we've been seeing.

(Bitbake rev: d89358c7b8aa69f12b8c384c4fdb493782633494)

(From poky rev: 1d987b98ed9ee95239f966ce990c119531e95d88)

Change-Id: I78540176a395b5051a8661e5a069dfba7041a6f8
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/poky/bitbake/lib/bb/server/process.py b/poky/bitbake/lib/bb/server/process.py
index 28b8eb9..80a7875 100644
--- a/poky/bitbake/lib/bb/server/process.py
+++ b/poky/bitbake/lib/bb/server/process.py
@@ -499,6 +499,7 @@
                 except IOError as e:
                     if e.errno == errno.EWOULDBLOCK:
                         pass
+                    raise
         finally:
             os.chdir(cwd)