cosmetic: make osmo-python-tests dependency more accurate

Change-Id: I4f84a13b7fa6ec4173bdc155e6114d4d7328b619
diff --git a/configure.ac b/configure.ac
index e2bbf79..e1c3303 100644
--- a/configure.ac
+++ b/configure.ac
@@ -207,7 +207,7 @@
 	AM_PATH_PYTHON
 	AC_CHECK_PROG(OSMOTESTEXT_CHECK,osmotestvty.py,yes)
 	 if test "x$OSMOTESTEXT_CHECK" != "xyes" ; then
-		AC_MSG_ERROR([Please install osmocom-python to run the VTY/CTRL tests.])
+		AC_MSG_ERROR([Please install git://osmocom.org/python/osmo-python-tests to run the VTY/CTRL tests.])
 	fi
 fi
 AC_MSG_CHECKING([whether to enable VTY/CTRL tests])