[jhbuild] Don't crash when the user removes builddir in the shell

[Ting-Wei Lan <lantw src gnome org>]

commit 154ce025a6431a348f44827cd37c8da83327c00f
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sat Apr 21 16:55:51 2018 +0800

    Don't crash when the user removes builddir in the shell
    
    It is sometimes necessary to remove the entire builddir in order to fix
    the build. When the user does this, JHBuild will fail to remove the
    symlink it created and the unlink call will fail and throw an exception.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=795431

 jhbuild/frontends/terminal.py |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/jhbuild/frontends/terminal.py b/jhbuild/frontends/terminal.py
index 37e498d..9b7552d 100644
--- a/jhbuild/frontends/terminal.py
+++ b/jhbuild/frontends/terminal.py
@@ -371,7 +371,10 @@ class TerminalBuildScript(buildscript.BuildScript):
                 uprint(_('exit shell to continue with build'))
                 os.system(user_shell)
                 if unlink_srcdir:
-                    os.unlink('.jhbuild-srcdir')
+                    try:
+                        os.unlink('.jhbuild-srcdir')
+                    except OSError:
+                        pass
                 os.chdir(cwd) # restor working directory
             elif val == '5':
                 self.config.reload()