[gnome-user-share] build: Fix ChangeLog generation with srcdir != builddir

[Bastien Nocera <hadess src gnome org>]

commit 4e3c18fcafce006d1cd3d6d03077cf8e34dec318
Author: Bastien Nocera <hadess hadess net>
Date:   Tue Aug 30 17:50:39 2016 +0200

    build: Fix ChangeLog generation with srcdir != builddir
    
    As done in jhbuild.

 Makefile.am |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index de7c75f..5f83339 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -20,7 +20,9 @@ AM_DISTCHECK_CONFIGURE_FLAGS = \
 # Build ChangeLog from GIT history
 ChangeLog:
        @if test -f $(top_srcdir)/.git/HEAD; then \
+               pushd $(top_srcdir) ; \
                git log --stat --after="Thu Jun 11 22:19:01 2009" > $@; \
+               popd ; \
        fi
 
 dist: ChangeLog