pgsql: Add cancel handlers so it's possible to Ctrl-C clusterdb,

Log Message:
-----------
Add cancel handlers so it's possible to Ctrl-C clusterdb, reindexdb
and vacuumdb.
ITAGAKI Takahiro, with minor fixes from me.

Modified Files:
--------------
    pgsql/src/bin/scripts:
        clusterdb.c (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/clusterdb.c.diff?r1=1.16&r2=1.17)
        common.c (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/common.c.diff?r1=1.25&r2=1.26)
        common.h (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/common.h.diff?r1=1.16&r2=1.17)
        reindexdb.c (r1.9 -> r1.10)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/reindexdb.c.diff?r1=1.9&r2=1.10)
        vacuumdb.c (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/vacuumdb.c.diff?r1=1.16&r2=1.17)