Added precheck that curl supports the 'openssl' engine in test 307.

tests/libtest/test307.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+# Determine if the given curl executable supports the 'openssl' SSL engine
+if ( $#ARGV != 0 ) 
+{
+	print "Usage: $0 curl-executable\n";
+	exit 3;
+}
+if (!open(CURL, "@ARGV[0] -s --engine list|"))
+{
+	print "Can't get SSL engine list\n";
+	exit 2;
+}
+while( <CURL> )
+{
+    exit 0 if ( /openssl/ );
+}
+close CURL;
+print "openssl engine not supported\n";
+exit 1;