Remove unused PHP functions from XSL

[ctgraham]

The registration of PHP functions in the XSLT processor:

aspace_findingaid/src/ArchivesSpaceIterator.php

Line 186 in 1717858

$xsl_proc->registerPHPFunctions();

and the PHP function namespace in the XSLT:

aspace_findingaid/src/uls_ead.xslt

Lines 7 to 9 in 1717858

	xmlns:php="http://php.net/xsl"
	xsl:extension-element-prefixes="php"
	exclude-result-prefixes="xsl ead xlink php"

both serve to enable calling PHP from the XSLT in the Islandora 7 Manuscript Solution Pack here:

aspace_findingaid/src/uls_ead.xslt

Line 387 in 1717858

<xsl:value-of select="php:function('islandora_manuscript_build_flat_query_url', ead:container)" />

and here:

aspace_findingaid/src/uls_ead.xslt

Line 429 in 1717858

<xsl:value-of select="php:function('islandora_manuscript_build_parented_query_url', current(), $containers)" />

Neither function exists in Islandora 2.x, so this orphaned code should all be removed, including the unused $call_query_link variable.