perf tools: Fix libdw-dev package name in error message

The headers required for DWARF support are provided by the libdw-dev
package in Debian-based distros.  This patch corrects the elfutils-dev
package name to libdw-dev in the Makefile error message when libdw.h is
not found.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1272292023-9869-1-git-send-email-stefanha@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile

@@ -504,7 +504,7 @@ PERFLIBS = $(LIB_FILE)
 
 ifndef NO_DWARF
 ifneq ($(shell sh -c "(echo '\#include <dwarf.h>'; echo '\#include <libdw.h>'; echo 'int main(void) { Dwarf *dbg; dbg = dwarf_begin(0, DWARF_C_READ); return (long)dbg; }') | $(CC) -x c - $(ALL_CFLAGS) -I/usr/include/elfutils -ldw -lelf -o $(BITBUCKET) $(ALL_LDFLAGS) $(EXTLIBS) "$(QUIET_STDERR)" && echo y"), y)
-	msg := $(warning No libdw.h found or old libdw.h found, disables dwarf support. Please install elfutils-devel/elfutils-dev);
+	msg := $(warning No libdw.h found or old libdw.h found, disables dwarf support. Please install elfutils-devel/libdw-dev);
 	NO_DWARF := 1
 endif # Dwarf support
 endif # NO_DWARF