configure: fix datadir after avconv merge

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -65,7 +65,7 @@ Standard options:
   --disable-logging        do not log configure debug information
   --prefix=PREFIX          install in PREFIX [$prefix]
   --bindir=DIR             install binaries in DIR [PREFIX/bin]
-  --datadir=DIR            install data files in DIR [PREFIX/share/avconv]
+  --datadir=DIR            install data files in DIR [PREFIX/share/ffmpeg]
   --libdir=DIR             install libs in DIR [PREFIX/lib]
   --shlibdir=DIR           install shared libs in DIR [PREFIX/lib]
   --incdir=DIR             install includes in DIR [PREFIX/include]
@@ -1633,7 +1633,7 @@ logfile="config.log"
 # installation paths
 prefix_default="/usr/local"
 bindir_default='${prefix}/bin'
-datadir_default='${prefix}/share/avconv'
+datadir_default='${prefix}/share/ffmpeg'
 incdir_default='${prefix}/include'
 libdir_default='${prefix}/lib'
 mandir_default='${prefix}/share/man'