Rename argon2-20181209.tar.gz to argon2.tar.gz so name keeps consistent

like all the other shipped libs.

configure

@@ -8090,12 +8090,12 @@ cur_dir=`pwd`
 cd extras
 rm -rf argon2-$argon2_version argon2
 if test "x$ac_cv_path_GUNZIP" = "x" ; then
-	tar xfz argon2-$argon2_version.tar.gz
+	tar xfz argon2.tar.gz
 else
-	cp argon2-$argon2_version.tar.gz argon2-$argon2_version.tar.gz.bak
-	gunzip -f argon2-$argon2_version.tar.gz
-	cp argon2-$argon2_version.tar.gz.bak argon2-$argon2_version.tar.gz
-	tar xf argon2-$argon2_version.tar
+	cp argon2.tar.gz argon2.tar.gz.bak
+	gunzip -f argon2.tar.gz
+	cp argon2.tar.gz.bak argon2.tar.gz
+	tar xf argon2.tar
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: compiling Argon2 library" >&5
 printf "%s\n" "compiling Argon2 library" >&6; }

configure.ac

@@ -640,12 +640,12 @@ dnl remove old argon2 directory to force a recompile...
 dnl and remove its installation prefix just to clean things up.
 rm -rf argon2-$argon2_version argon2
 if test "x$ac_cv_path_GUNZIP" = "x" ; then
-	tar xfz argon2-$argon2_version.tar.gz
+	tar xfz argon2.tar.gz
 else
-	cp argon2-$argon2_version.tar.gz argon2-$argon2_version.tar.gz.bak
-	gunzip -f argon2-$argon2_version.tar.gz
-	cp argon2-$argon2_version.tar.gz.bak argon2-$argon2_version.tar.gz
-	tar xf argon2-$argon2_version.tar
+	cp argon2.tar.gz argon2.tar.gz.bak
+	gunzip -f argon2.tar.gz
+	cp argon2.tar.gz.bak argon2.tar.gz
+	tar xf argon2.tar
 fi
 AC_MSG_RESULT(compiling Argon2 library)
 cd argon2-$argon2_version