Python: fixed interpreter path in ./configure.

auto/modules/python

@@ -68,7 +68,6 @@ if /bin/sh -c "$NXT_PYTHON_CONFIG --prefix" >> $NXT_AUTOCONF_ERR 2>&1; then
         NXT_PYTHON_CONFIG="${NXT_PYTHON_CONFIG} --embed"
     fi
 
-    NXT_PYTHON_EXEC=`${NXT_PYTHON_CONFIG} --exec-prefix`/bin/${NXT_PYTHON}
     NXT_PYTHON_INCLUDE=`${NXT_PYTHON_CONFIG} --includes`
     NXT_PYTHON_LIBS=`${NXT_PYTHON_CONFIG} --ldflags`
 
@@ -133,7 +132,7 @@ fi
 
 NXT_PYTHON_MOUNTS_HEADER=$NXT_BUILD_DIR/nxt_python_mounts.h
 
-$NXT_PYTHON_EXEC -c 'import os.path
+$NXT_PYTHON -c 'import os.path
 import sys
 pyver = "python" + str(sys.version_info[0]) + "." + str(sys.version_info[1])