package/c-icap: remove configure option process-mutexes

This option was removed in 2014:
https://sourceforge.net/p/c-icap/code/1102/#diff-3

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/c-icap/c-icap.mk

@@ -12,7 +12,6 @@ C_ICAP_LICENSE_FILES = COPYING
 C_ICAP_INSTALL_STAGING = YES
 C_ICAP_CONFIG_SCRIPTS = c-icap-config c-icap-libicapapi-config
 C_ICAP_CONF_OPTS = \
-	--with-process-mutexes=posix \
 	--without-perl \
 	--enable-large-files \
 	--enable-ipv6