bitbake: perforce.py: fix the perforce fetcher

The bb.process.run() will return one tuple, e.g:

p4file = ('strA\nStrB\nstrC\n'), then there will be an iteration on p4file:

for i in p4file:
	[snip]

The i will be 's t r A ...', this is incorrect. use splitlines() to fix
the problem.

[YOCTO #3619]

(Bitbake rev: b7440fb36b419996046f607e66434ce34722272b)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/fetch2/perforce.py

@@ -170,7 +170,7 @@ class Perforce(FetchMethod):
         logger.info("Fetch " + loc)
         logger.info("%s%s files %s", p4cmd, p4opt, depot)
         p4file, errors = bb.process.run("%s%s files %s" % (p4cmd, p4opt, depot))
-        p4file = p4file.strip()
+        p4file = [f.rstrip() for f in p4file.splitlines()]
 
         if not p4file:
             raise FetchError("Fetch: unable to get the P4 files from %s" % depot, loc)