[parted] ped_partition_busy should not call the libparted exception handler

[Hans de Goede]

Modify libparted/arch/linux.c _partition_get_part_dev() to not call
_device_stat() but instead use stat directly, as _device_stat() calls
the libparted exception handler and we don't want this here, the only caller
of _partition_get_part_dev() is _partition_is_mounted(), which in turn only
gets called by linux_partition_is_busy(), and we don't want to "throw"
exceptions from ped_partition_busy()

This issue was noticed in combination with pyparted as used by anaconda, see:
https://bugzilla.redhat.com/show_bug.cgi?id=527035#c10
---
 libparted/arch/linux.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index 52f7d21..a8d6daf 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -2127,7 +2127,7 @@ _partition_get_part_dev (const PedPartition* part)
         struct stat dev_stat;
         int dev_major, dev_minor;
 
-        if (!_device_stat (part->disk->dev, &dev_stat))
+        if (stat (part->disk->dev->path, &dev_stat))
                 return (dev_t)0;
         dev_major = major (dev_stat.st_rdev);
         dev_minor = minor (dev_stat.st_rdev);
@@ -2184,6 +2184,8 @@ _partition_is_mounted (const PedPartition *part)
         if (!ped_partition_is_active (part))
                 return 0;
         dev = _partition_get_part_dev (part);
+        if (!dev)
+               return 0;
         return _partition_is_mounted_by_dev (dev);
 }
 
-- 
1.6.5.rc2