scripts: Fix return value checks from subprocess.call()'s

Python function subprocess.call() returns the return value of the
executed process. If return values are not checked, errors may
go unnoticed and bad things can happen.

Change all callers of subprocess.call() which do not check for
the return value to use subprocess.check_call() which raises
CalledProcessError if the subprocess returns with non-zero value.

https://docs.python.org/2/library/subprocess.html#using-the-subprocess-module

All users of the function were found with:

$ git grep "subprocess\.call" | \
  egrep -v 'if.*subprocess\.call|=\ +subprocess\.call|return.*subprocess\.call'

Tested similar patch on top of yocto jethro. Only compile tested
core-image-minimal on poky master branch.

(From OE-Core rev: 031cf9c7834cd1cba8b03832673a3e3cfcbfae7c)

Signed-off-by: Mikko Rapeli <mikko.rapeli@bmw.de>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/runqemu

@@ -1098,7 +1098,7 @@ class BaseConfig(object):
         if self.serialstdio:
             logger.info("Interrupt character is '^]'")
             cmd = "stty intr ^]"
-            subprocess.call(cmd, shell=True)
+            subprocess.check_call(cmd, shell=True)
 
             first_serial = ""
             if not re.search("-nographic", self.qemu_opt):
@@ -1146,7 +1146,7 @@ class BaseConfig(object):
         if self.cleantap:
             cmd = 'sudo %s %s %s' % (self.qemuifdown, self.tap, self.bindir_native)
             logger.info('Running %s' % cmd)
-            subprocess.call(cmd, shell=True)
+            subprocess.check_call(cmd, shell=True)
         if self.lock_descriptor:
             logger.info("Releasing lockfile for tap device '%s'" % self.tap)
             self.release_lock()
@@ -1155,11 +1155,11 @@ class BaseConfig(object):
             logger.info("Shutting down the userspace NFS server...")
             cmd = "runqemu-export-rootfs stop %s" % self.rootfs
             logger.info('Running %s' % cmd)
-            subprocess.call(cmd, shell=True)
+            subprocess.check_call(cmd, shell=True)
 
         if self.saved_stty:
             cmd = "stty %s" % self.saved_stty
-            subprocess.call(cmd, shell=True)
+            subprocess.check_call(cmd, shell=True)
 
         if self.clean_nfs_dir:
             logger.info('Removing %s' % self.rootfs)