Be more selective in python version extraction in configure.

... where "selective" means | head -1.  Some pythons spew not only their
version but also the compiler version, so we were getting a multi-line
value for PYTHON_VERSION in some places, which breaks the generated
GNUMakefiles.  configure must be setting some env var that is causing
newer or custom-built pythons to produce this extra information.
Anyway, head -1 should be a fine strategy.

clientside/configure

@@ -4239,7 +4239,7 @@ if test x"$PYTHON" = x""; then
     as_fn_error $? "python not detected" "$LINENO" 5
 fi
 
-PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2`
+PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2 | head -1`
 PYTHON_PATH=`dirname ${PYTHON}`
 if test ! -d "$PYTHON_PATH/include"; then
     PYTHON_PATH=`dirname ${PYTHON_PATH}`

clientside/configure.ac

@@ -207,7 +207,7 @@ if test x"$PYTHON" = x""; then
     AC_MSG_ERROR([python not detected])
 fi
 
-PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2`
+PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2 | head -1`
 PYTHON_PATH=`dirname ${PYTHON}`
 if test ! -d "$PYTHON_PATH/include"; then
     PYTHON_PATH=`dirname ${PYTHON_PATH}`

configure

@@ -2765,7 +2765,7 @@ if test x"$PYTHON" = x""; then
     as_fn_error $? "python not detected" "$LINENO" 5
 fi
 
-PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2`
+PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2 | head -1`
 PYTHON_PATH=`dirname ${PYTHON}`
 if test ! -d "$PYTHON_PATH/include"; then
     PYTHON_PATH=`dirname ${PYTHON_PATH}`

configure.ac

@@ -83,7 +83,7 @@ if test x"$PYTHON" = x""; then
     AC_MSG_ERROR([python not detected])
 fi
 
-PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2`
+PYTHON_VERSION=`${PYTHON} -V 2>&1 | cut -d ' ' -f 2 | cut -d '.' -f 1,2 | head -1`
 PYTHON_PATH=`dirname ${PYTHON}`
 if test ! -d "$PYTHON_PATH/include"; then
     PYTHON_PATH=`dirname ${PYTHON_PATH}`