LP#1657282: fix redirect of one-hit metarecord searches

LP#1657282: fix redirect of one-hit metarecord searches

This patches fixes a bug where, when performing a metarecord
("Group Formats and Editions") search, one-hit result sets
get redirected to a "/eg/opac/record/0.0..." page, which
results in a "Bad Request" error being shown to the user.

To test:

[1] Perform a metarecord search that would result in exactly
    one metarecord search. Observe that the browser displays
    a "Bad Request" error page.
[2] Apply the patch and perform step 1 again. This time, the
    search should succeed. Note that if the metarecord contains
    more than one component, a results page with one grouped
    hit is displayed; if the metarecord has exactly one component,
    that bib's record page is displayed.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>
Signed-off-by: Kathy Lussier <klussier@masslnc.org>