Remove un-needed braces around single statements.

contrib/array/array_iterator.c

contrib/datetime/datetime_functions.c

contrib/string/string_io.c

src/backend/access/common/heaptuple.c

src/backend/access/common/indextuple.c

src/backend/access/common/indexvalid.c

src/backend/access/common/tupdesc.c

src/backend/access/gist/gist.c

src/backend/access/gist/gistget.c

src/backend/access/gist/gistscan.c

src/backend/access/hash/hashinsert.c

src/backend/access/hash/hashovfl.c

src/backend/access/hash/hashpage.c

src/backend/access/hash/hashscan.c

src/backend/access/hash/hashsearch.c

src/backend/access/heap/heapam.c

src/backend/access/index/genam.c

src/backend/access/index/istrat.c

src/backend/access/nbtree/nbtinsert.c

src/backend/access/nbtree/nbtree.c