cache: Do not configure cache[pool] support by default

Users wanting cache[_pool] segment type support need to include
"--with-cache=internal" when configure'ing.

configure

@@ -1625,7 +1625,7 @@ Optional Packages:
   --with-thin-dump=PATH   thin_dump tool: [[autodetect]]
   --with-thin-repair=PATH thin_repair tool: [[autodetect]]
   --with-cache=TYPE       cache support: internal/shared/none
-                          [[TYPE=internal]]
+                          [[TYPE=none]]
   --with-ocfdir=DIR       install OCF files in DIR
                           [[PREFIX/lib/ocf/resource.d/lvm2]]
   --with-default-pid-dir=PID_DIR
@@ -7543,7 +7543,7 @@ $as_echo_n "checking whether to include cache... " >&6; }
 if test "${with_cache+set}" = set; then :
   withval=$with_cache; CACHE=$withval
 else
-  CACHE=internal
+  CACHE=none
 fi
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CACHE" >&5

configure.in

@@ -482,8 +482,8 @@ AC_MSG_CHECKING(whether to include cache)
 AC_ARG_WITH(cache,
 	    AC_HELP_STRING([--with-cache=TYPE],
 			   [cache support: internal/shared/none
-			    [[TYPE=internal]]]),
-	    CACHE=$withval, CACHE=internal)
+			    [[TYPE=none]]]),
+	    CACHE=$withval, CACHE=none)
 AC_MSG_RESULT($CACHE)
 
 if [[ "x$CACHE" != xnone -a "x$CACHE" != xinternal -a "x$CACHE" != xshared ]];