curl: add wrapper to read key/cert from git if available

Signed-off-by: Alejandro Mery <amery@geeks.cl>

files/bin/curl

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+CERT="$(git config http.sslcert 2> /dev/null)"
+KEY="$(git config http.sslkey 2> /dev/null)"
+
+exec /usr/bin/curl \
+	${KEY:+--key "$KEY"} \
+	${CERT:+--cert "$CERT"} \
+	"$@"