bootstrap: remove forced m4 directory

It's defined in configure.ac since e8df55c488
which is more recent than 77e5b00d85 and
2799d36bc8.

Makefile.am

@@ -39,7 +39,6 @@ AM_DISTCHECK_CONFIGURE_FLAGS = \
 	--disable-fribidi \
 	--with-kde-solid='$${datadir}/kde4/apps'
 
-ACLOCAL_AMFLAGS = -I m4
 AUTOMAKE_OPTIONS = \
 	1.11 \
 	-Wall \

bootstrap

@@ -17,8 +17,6 @@ if test "$#" != "0"; then
   exit 1
 fi
 
-ACLOCAL_ARGS="-I m4 ${ACLOCAL_ARGS}"
-
 # Check for tools directory
 if test -z ${VLC_TOOLS}; then
   VLC_TOOLS=extras/tools/build