Revert "pkg.m4: PKG_CHECK_MODULES provides modversion"

This reverts commit 8d9d3de6eb.

pkg.m4

@@ -146,7 +146,6 @@ AC_MSG_CHECKING([for $2])
 
 _PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
 _PKG_CONFIG([$1][_LIBS], [libs], [$2])
-_PKG_CONFIG([$1][_VERSION], [modversion], [$2])
 
 m4_define([_PKG_TEXT], [Alternatively, you may set the environment variables $1[]_CFLAGS
 and $1[]_LIBS to avoid the need to call pkg-config.
@@ -187,7 +186,6 @@ To get pkg-config, see <http://pkg-config.freedesktop.org/>.])[]dnl
 else
         $1[]_CFLAGS=$pkg_cv_[]$1[]_CFLAGS
         $1[]_LIBS=$pkg_cv_[]$1[]_LIBS
-        $1[]_VERSION=$pkg_cv_[]$1[]_VERSION
         AC_MSG_RESULT([yes])
         $3
 fi[]dnl