Begin a search from the extremity of the selected region instead of from the
cursor position. Previously when changing search direction the first
"result" is the same  as has been previously found when searching forwards as
the cursor is at the end of the selection, and the search region is from the
end of the previous result to the begin of the document. Now the selected
or previously found region is ignored. This only affects normal searches,
and does not have any effect when multiple regions are selected.

Change-Id: I65a5d94b898dd4b7467889b1932f42c9b6b523fe
Reviewed-on: https://gerrit.libreoffice.org/4061Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>