remove the configure file which is generated by autoconf

As suggested by Yegor the configure script is generated by autoconf anyway.
So remove this generated file and update the README.md documentation to point
to the autoconf invocation which is now needed first.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>

README.md

@@ -8,6 +8,7 @@ Installation
 
 To build and run socketcand make sure you have the following tools installed:
 
+* autoconf
 * make
 * gcc or another C compiler
 * a kernel that includes the SocketCAN modules
@@ -16,6 +17,12 @@ To build and run socketcand make sure you have the following tools installed:
 
 First run
 
+    $ autoconf
+
+to create the 'configure' script.
+
+Then run the created script with
+
     $ ./configure
 
 to check your system and create the Makefile. If you want to install scripts for a init system other than SysVinit check the available settings with './configure -h'.