package/filemq: bump to the latest master

This bump include a patch that fixes a build issue with gcc >= 7.1.

Fixes:
http://autobuild.buildroot.net/results/434/43452430edf44cbcef6ea3a5ab80ac0ff406208f

Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/filemq/filemq.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256 a9973117f8afea6d4cbde95e4d7f46ab90d67cb0d72e42165410d665bf1765c1  filemq-3dc89932903b0320853d87833aabc6f7e7781c49.tar.gz
+sha256 f3764e1adacfbf7fd09fb9c553e796a80d8159f1ace689fb68307afbc1746d4c  filemq-8940f34e0f1c8f25c1c693ed8db069f58fbc5ad0.tar.gz

package/filemq/filemq.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-FILEMQ_VERSION = 3dc89932903b0320853d87833aabc6f7e7781c49
+FILEMQ_VERSION = 8940f34e0f1c8f25c1c693ed8db069f58fbc5ad0
 FILEMQ_SITE = $(call github,zeromq,filemq,$(FILEMQ_VERSION))
 
 FILEMQ_AUTORECONF = YES