Why libxml2 version errors are seen when running cluster commands on Red Hat Enterprise Linux?

Issue

• pcs cluster status gives me `libxml2.so.2: no version information available errors.

# pcs cluster status
Cluster Status:
 /usr/sbin/crm_mon: /lib/libxml2.so.2: no version information available (required by /lib64/libpe_status.so.4)
 /usr/sbin/crm_mon: /lib/libxml2.so.2: no version information available (required by /lib64/libstonithd.so.2)
 /usr/sbin/crm_mon: /lib/libxml2.so.2: no version information available (required by /lib64/libpengine.so.4)
(...)

• This error is printed every time a cluster command is used:

# cman_tool version -r
cman_tool: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by /usr/lib64/libccs.so.3)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
xmllint: /app/test/linux2.6-glibc2.3-x86_64/lib/libxml2.so.2: no version information available (required by xmllint)
Warning: program compiled against libxml 207 using older 206
Relax-NG validity error : Extra element fence in interleave
tempfile:6: element fence: Relax-NG validity error : Element clusternode failed to validate content
tempfile:5: element clusternode: Relax-NG validity error : Element clusternodes has extra content: clusternode
Relax-NG validity error : Extra element fencedevices in interleave
tempfile:55: element fencedevices: Relax-NG validity error : Element cluster failed to validate content
Configuration fails to validate
cman_tool: Not reloading, configuration is not valid