populate_sdk_ext: We now require python3, not python

We no longer expect a "python" binary in PATH so update the eSDK's
expectations to match. This was the only failure on autobuilder test
systems with python missing.

(From OE-Core rev: 946ce21b10dcad506edcaadb4e4242c049e4c316)

(From OE-Core rev: 775336424bcc7c083e2ac6ccd3db0b16e87dc29a)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/populate_sdk_ext.bbclass

@@ -574,8 +574,8 @@ sdk_ext_preinst() {
 		exit 1
 	fi
 	# The relocation script used by buildtools installer requires python
-	if ! command -v python > /dev/null; then
-		echo "ERROR: The installer requires python, please install it first"
+	if ! command -v python3 > /dev/null; then
+		echo "ERROR: The installer requires python3, please install it first"
 		exit 1
 	fi
 	missing_utils=""