base: use single job to build ipmiComm.

Using with multiple processes breaks the build, as interdependencies are
not properly handled when generating the substituted databases. Use a
single process for this specific module, so that local builds of other
modules can use multiple jobs without breaking.

base/install_modules.sh

@@ -71,7 +71,7 @@ EPICS_BASE
 
 download_from_github slac-epics-modules ipmiComm $IPMICOMM_VERSION
 patch -d ipmiComm -Np1 < ipmicomm.patch
-install_module ipmiComm IPMICOMM "
+JOBS=1 install_module ipmiComm IPMICOMM "
 EPICS_BASE
 ASYN
 "