MB-10682: Make the script relocatable

Previously we hardcoded the absolute path of the installed binary
into the wrapper script. This patch determines the path at
runtime.

Limitation:
  The directory layout have to be:

  bin/tools/program
  lib/python/python-file

Change-Id: Ia2139ec59c7cb92bdf28b2caabc504075f03f282
Reviewed-on: http://review.couchbase.org/35543
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>

CMakeLists.txt

@@ -2,7 +2,7 @@ PROJECT(CouchbasePythonClient)
 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 # Generate the python wrappers
-CONFIGURE_FILE (${CMAKE_CURRENT_SOURCE_DIR}/wrapper/wrapper.in
+CONFIGURE_FILE (${CMAKE_CURRENT_SOURCE_DIR}/wrapper/wrapper
                 ${CMAKE_CURRENT_BINARY_DIR}/wrapper/cbdocloader)
 
 INSTALL(PROGRAMS

wrapper/wrapper.in → wrapper/wrapper

@@ -1,5 +1,10 @@
 #! /bin/sh
-root=${CMAKE_INSTALL_PREFIX}/lib/python
+
+CWD="`pwd`"
+D0="`dirname "$0"`"
+cd $D0/../../lib/python
+root="`pwd`"
+cd "$CWD"
 
 if test -z "$PYTHONPATH"; then
    PYTHONPATH="$root"