makefile: fix python 2/3 detection in the Makefile

Fix detection of python in a non-python3 environment.
The old path always used python3.  The 2 fixes here are:
 a.) escape the '$' before the subshell.
 b.) use shell builtin 'command -v' rather than 'which' in case
     'which' is not available.

1 files changed, 2 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 09cd1479..821be4b5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CWD=$(shell pwd)
 PYVER ?= $(shell for p in python3 python2; do \
-	out=$(which $$p 2>&1) && echo $$p && exit; done; \
-	exit 1)
+	out=$$(command -v $$p 2>&1) && echo $$p && exit; done; exit 1)
+
 noseopts ?= -v
 
 YAML_FILES=$(shell find cloudinit bin tests tools -name "*.yaml" -type f )