Fix #466, leak of memory after call pq

Revealed by sequence from test 321:
INSERT INTO pq VALUES ( 'test' );
CALL PQ ('pq', 'test 1', 1 as docs, 0 as docs_json );

(RAM segment is created during call, and not deleted at the end)

src/sphinxrt.cpp

@@ -11879,6 +11879,7 @@ bool PercolateIndex_c::MatchDocuments ( ISphRtAccum * pAccExt, PercolateMatchRes
	BuildSegmentInfixes ( pSeg, m_pDict->HasMorphology(), true, m_tSettings.m_iMinInfixLen, PERCOLATE_WORDS_PER_CP, ( m_iMaxCodepointLength>1 ) );

	DoMatchDocuments ( pSeg, tRes );
	SafeDelete ( pSeg );

	// done; cleanup accum
	pAcc->m_dAccum.Resize ( 0 );