gnucash maint: Add engine-common.i to EXTRA_DIST for consistency.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/2b895aa7 (commit)
	from  https://github.com/Gnucash/gnucash/commit/f4e8d9a6 (commit)



commit 2b895aa79d019ac7f220003bc0070c4f2ed6cac5
Author: John Ralls <jralls at ceridwen.us>
Date:   Tue Sep 29 14:02:49 2015 -0700

    Add engine-common.i to EXTRA_DIST for consistency.



Summary of changes:
 src/engine/Makefile.am | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)