[meld] Show error dialog when we can't run 'patch' (closes bgo#636093)

[Kai Willadsen <kaiw src gnome org>]

commit 52e2f329d82f7350f369691b7c9f9eaa4afcd350
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sat Jan 15 07:35:43 2011 +1000

    Show error dialog when we can't run 'patch' (closes bgo#636093)

 meld/vcview.py |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/meld/vcview.py b/meld/vcview.py
index f0b080a..cafb5a4 100644
--- a/meld/vcview.py
+++ b/meld/vcview.py
@@ -531,8 +531,13 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
                 open(destfile,"w").close()
             diffs.append( (destfile, pathtofile) )
 
-        patchcmd = self.vc.patch_command( tmpdir )
-        if misc.write_pipe(patchcmd, patch, error=misc.NULL) == 0:
+        patchcmd = self.vc.patch_command(tmpdir)
+        try:
+            result = misc.write_pipe(patchcmd, patch, error=misc.NULL)
+        except OSError:
+            result = 1
+
+        if result == 0:
             for d in diffs:
                 os.chmod(d[0], 0444)
                 self.emit("create-diff", d)